AIBU to not compromise on my daughters birthday dinner for the sake of my niece and nephews

These kids eat plain pasta, or chicken nuggets that look a specific way/from a specific place.
That's a bit more than just 'perceiving the foods you like in a different way'.

This 100%

It would not cross my mind to ask for something so completely different that’s not on the menu. I might ask for say no sauce on the chicken dish if possible, but to ask for a dish that’s not on the menu, like pizza instead of fish, is a new one for me.

If you are a large group booking you might as they may be more willing to cook something different. Sometimes for particularly fancy restaurants they will stipulate they can’t offer anything different off the menu

As she is turning 12 I am guessing your Dd wants to feel she is having a ‘grown up’ dinner, not Frankie and Benny’s.

Is this normal behaviour? Do people honestly ring up a nice fish restaurant and ask if they can make pizza instead, and they say yes of course we can? I have never come across this kind of thing.

Because maybe for once DD would like to go to a restaurant of her choice on her birthday and share it with extended family, the majority of which also want to eat at the restaurant. There are 3 picky eaters who could eat chips at the very least and am sure will have a sweet tooth. The restaurant could also I am sure provide something plain for them

The family usually have to compromise for brother’s family. For once maybe brother’s family have to compromise

It's her birthday. Why on earth should it be all about planning an enjoyable day for others if she might not enjoy it as much as she'd enjoy the seafood place?
Interacting socially is not all about being some kind of event planner. The brother could do with a lesson in parenting his kids. They need to learn that sometimes you do things you'd not do as a first choice, if they mean a lot to someone you love. And that something like eating first, then having a side or a pudding at the restaurant the other person has chosen, is a good workaround.

Good God.
The DD wants to go to a particular restaurant, and would love her wider family to be there.

This in spades . Exactly what I was trying to articulate yet you've done it better

She needs to decide what she wants from the meal. If it is to enjoy the food stick with the restaurant, if it is to enjoy a meal with her cousins change the restaurant. It's ok to say this time the food wins and it's up to your brother to decide whether spending the time with their cousin and having less than ideal food is better than not going at all.

My daughter has many allergies, is borderline ARFID and has feeding issues related to severe reflux. It is a pain eating out with her. There are times when we eat our with family and we pick places where we know they are good at accommodating her dietary requirements and cooking her something related to the food on the menu but there are also times when we want to go out and enjoy some good food. We do this when she's not around or we do a early afternoon meal when she can a small not quite a meal of foods that she can eat but then has a dinner when she is at home later on. We have arranged her birthday party this year to be 1-3 to avoid a meal time, we will provide plenty of snacks and food for the rest of the children but it means we don't have to have a battle with the about food on her birthday in front of her friends.

For a bit of variety though for a child with a very restricted diet she has a broad palate and struggles most with "beige" foods. Pasta is the only beige food she will eat but her favourite foods are sauerkraut and capers that said there is only 1 variety of oat milk she will drink, she loves fruit and veg but struggles with textures and strength of flavours. Carrots can't be raw but they can't be over cooked. There is a fine window when bananas are ok not so green that they can't be opened but not too yellow, regular broccoli is too mushy when cooked but tender stem is ok.

There is definitely a genetic component too, her and her grandmother hate avocado, my mother-in-law says it tastes like soap and the face she pulled at a toddler would suggest she tastes the same.

To answer the question someone asked about fussy eaters.

1. She is supplemented, she has a multivitamin, omega 3,6,9 (fish allergy), a target per day of oat milk (dairy allergy) to ensure she is getting enough calcium and iodine and as she's barely gained any weight in the last 2 years also has fortified drinks on prescription.
2. She has school dinners, the council provide her with a complete menu that meets her nutritional needs and the chef in the school does some minor tweaks to ensure she enough food to eat. She has a staff member on her table to encourage her to eat as she has very low appetite and eating is an inconvenience for her.
3. We are in the scouts and whilst we have only done day trips so far we discuss food with whoever is handling the meals and trying to get something she can and will eat. We also bring along matching food to avoid being caught out. I also joined as a leader so that I have oversight and can support her and other children that have dietary needs.

For the millionth time, there isn't only fish available.

Sorry but being veggie is quite different to seafood when quite a lot of people don’t like seafood. Also this is children. Bit different if it were adults.
But the fish dishes aren't all lobster tartare or sashimi. There's fish and chips on the menu.
Not to mention non-fish dishes.
These kids are exceptionally fussy.

Im in the minority. Her birthday her choice, there is NOTHING they will eat?. I dont believe that , even the best fish resturants serve alternatives, why should she back down. When will lines be drawn before people she has to back down to everyone . Party for friends , meal with family and people on here suggesting the O.P.does ANOTHER meal . Shes 12 , not 21
This is why I.dont do family stuff , there is always one that will moan.
How does his kids feel about missing out or has your brother decided to be family spokesman?

Could you check with the restaurant if they could do a set menu for the fussy kids, could like do chicken nuggets or pizza or something equally benign?
I agree it is her choice and that is where she wants to go.

So why did you invite them then?

They are family

Its a perfectly normal way to say it

We've been the couple being subsidised at meals we couldn't afford to pay for and later in life we've been the couple that made the same offer to family members who we wanted to come to a meal they couldn't afford to pay

We offer to pay because they would turn down the invitation otherwise. We simply say we know its expensive and we really want you there so we will pay your tab, enjoy!

Some of the replies on here are batshit. Id say teaching a child that actually, it is perfectly reasonable at times to prioritize themselves, is extremely valuable, lest you want to train a doormat.

The cousins cannot always expect to be catered to. If the dinner doesn’t suit, they don’t have to attend.

There have been two threads alone today on here that have shown how willing people are to take from their own children to keep other children/adults happy.
I just cannot relate to that.

I don't see telling your parents when asked what you would like to do on your birthday is being a princess. We don't even know if she knows her cousins limited eating habits.
Who is being made miserable. I think her uncle is in danger of making her miserable if he can't manage his children's aberrations.

Your preference teaches yet another young woman she can't have what she lkes if some men/boys don't like it

Its her birthday. The one day in the years when all the choices should be hers, not a compromise that suits others, others who get to choose what they want on their birthdays

I bet the brother doesn’t pay for everyone when they all compromise and go to the exact 3 same restaurants every time .

Why do all the other extended family members who want to go have to miss out ?

Your Daughter gets to choose where she goes for her birthday @randomcar1990
I see you compromise every other time you go out to eat as a family. Does your DB normally make everything about him and his children?
You would think, as an adult, he would tell his kids to suck it up for once wouldn't you? For the sake of his Neices birthday?
I think a point needs to be made here that not every occasion revolves around them.

Keep the reservation at the Fish restaurant OP. I hope you all have a lovely time.

For sure this!
Also you should have just offered to pay for the restaurant for the guests. Saying that you’ll help pay if people need you to is not a nice way of doing things.