How far would put your convictions/beliefs first?

[Eart]

Would you stick to your beliefs even if it meant losing family?
Ie, you don't accept pronouns changes but you accept female name and make an effort to buy more female cards/gifts etc, compliment hair/make up etc of child

But you've been told that by not using female pronouns or accepting the person whole as a female you'll be cut out of their lives (and lose all your other neices/nephews)

On an individual basis, I'd probably use the name. Avoid pronouns. And anything referring to niece/nephew, for example I'd refer to them as ' my sister's child'. I'd buy non-gendered birthday cards and give money instead of gifts. I'd ignore/refuse to be drawn on saying anything else. Of challenged I'd say something like 'I love Sam for who Sam is and I'll always be there for Sam'.

On a wider/class/societal level though, I'd still be as GC as possible. I've discussed with my DH that I would have to resign from my job if I was really pushed about this at work, which could happen.

It seems like they've already decided how they're going to treat you, with very little respect, so I'm not sure why you're trying so hard to bow to them tbh. You're not being unreasonable, know that.
It's a crazy world we're living in.

I couldn't do it - the furthest I will go in support of someone I'm fond of, is using their chosen name. That's literally it. I won't validate a lie or a position that compromises my own integrity.

You won't be able to win on this or find a compromise you both can live with - for some people only total support of their position is good enough.

I suspect you're right about that. They know her husband won't comply but they think she can be controlled.