Can I do this? Or is it weird?!

[IHateThinkingUpANewUsername]

I’m debating giving baby2 (if a girl) the feminised (sp?) version of child1’s middle name(boy), as a first name. It’s not a family name, just so happens we like both names.

Not the real names but imagine:
Samuel Patrick with younger sister Patricia. ‘Samuel’ is only known as Sam, doesn’t get full named often so few people actually know his middle name...
The fact I’m trying to defend the situation makes me think it’s weird though!

It's fine. I doubt anyone will notice the connection. Most people don't know the middle names of others. Apart from my closest family and partner I couldn't tell you anyone else's middle name.

Not at all. My cousins were raised as Catholics (my Dad lapsed, but aunt most certainly didn't). One of the many sisters got given Marie as a middle name. Before too long another sister comes along and gets Marie as a first name!
Weirder than that, have been doing the family tree, and it turns out my grandmother (same branch) had a sister who died of Spanish flu as a baby, and when the next female baby was born they just gave her the same first name!

No one uses middle names so it’s fine,