Baby shower etiquette

Do I invite a sister-in-law who I barely ever see and do not particularly like just because "she's family?" What about a cousin's wife who I feel I should invite because she is close to her sisters-in-law who are my other cousins?

I am having a hard time making this list lol! And I know my mother-in-law is going to make it more difficult if I ask her opinion because she will tell me to invite everyone with a lot of money so I get good gifts which I refuse to do!! So third part to the question, do I have to ask my MIL who she wants to come from her side??

This shower will be predominantly family because I really only have one close friend and my other 2 best friends are my sisters...literally those will be the only people my age besides some cousins!