Brand New 8 week old kittens

[DameCelia]

Having waved our last foster dog off to its forever home we have decided to adopt some kittens, two eight week old bundles of fur arrive on Monday. We have only ever adopted older cats before, and they have all now passed away and their accessories been donated so we are starting from scratch.
I am assuming two litter trays (although all five of the litter are sharing one at the vet's), but what sort of litter? And are litter tray liners worth it? How about mats for under the litter trays?
Water bowl or fountain?
Feliway diffuser? or wait to see how they settle?
I will be buying a bag of the Royal Canin babycat dried food they are currently on then gradually moving them to another dried food, yet to decide which.
So many questions.
Can any kind Mumsnetters help with advice?
We do have a room set aside for them, and of course I will upload some photos

Wood pellet litter is good for kittens as it's the safest if they end up eating any (all the kittens I've known end up playing with bits of litter!). A tray per cat + one extra is the gold standard for adult cats so if you can have two, that would be great.

Tray liners have never worked with my cats as they all like to scratch and "dig" in their litter box and end up scratching the liners into shreds. I had a mat in front of trays to catch loose litter but don't think it makes a big difference so have stopped using those.

As PP said, At least two trays. More depends on the cats. We don’t have a lot of space so we only have two trays but our boy and girl are happy with two.
Start with a water bowl and see how much damage they do with that.
Invest in some anti-scratch spray for your furniture, maybe.
Scratching posts, throw rugs and toys with a wand for you to play with them, as well as small catnip toys. Cat tree if you’ve got the space.
Wait to see how they settle before investing in feliway.

Looking forward to the photos!

Uhm.... when did charities start adopting out 8 week old kittens?

LazyFace the OP said they were at the vets. Perhaps they were handed in there and staff have been hand feeding and/or rearing them.

Oooooooo kittens

Uuh exciting . Lots and lots of toys, one or two cat beds (closed ones), atleast one litter tray per cat (is recommended), I use chicken starter feed for litter, should be the same as world's best and it is corn, therefore it is okay if they lick it off their paws. Scratching post and I could go on .
This one is expensive but very good for kittens and combines above-mentioned.

Best of luck.