Who to invite to first birthday?

My little one turns ONE in two months!

I have been planning his party for months and have a theme, many decorations made and the food pretty much planned out.

But I'm stuck on a few things. We moved here just 6 months ago so I don't have a ton of friends. I have my parents and two siblings that live very close but my husbands are all across the country. I also recently joined a mommy group and have been slowly getting to know mom's there but we've never hung out outside the group so I don't know if it would be weird to invite them. Also, we live in an apartment so there's not a ton of space.

So originally I planned on just having a very small get together with my parents and 2 siblings. But the problem is, I really can't stand my sister. She has no boundaries when it comes to my child and it's to the point where I've been avoiding her for about 3 months. I want soooo badly to not invite her but I pretty much have to. She lives 10 mins away and the rest of the family will all be there. So do I do the small immediate family or go all out and invite the new mom friends? I think it would be cute to have all his baby friends there but at the same time our place is so small. His birthday is in November so I think it's too cold to go to a park or something and he's so young I don't want to pay for a room like at a trampoline place or magic mountain.

What would you do?