Is it being a bridezilla?

What do you mean by a folder? As in printing out something and handing it to them.
I personally would think that was over the top if I was in the party. Maybe a couple of meetings would be easier and more relaxed, even on zoom if you are not in the same area as them. I’ve had zoom calls with my mum about the bridesmaids dresses as we live 250 miles away from each other. Also send them diary invites for the important dates if they have email and Outlook for instance.

This sounds like a great idea to me personally but I love to be super organised. I think that anything that gives you peace of mind is worth doing, but particularly if your wedding party know you love to have everything planned out then they won't think you're a 'bridezilla' for giving them some information - they'll just think it's so you! If you still worry about how it could come across, how about making it look 'pretty'? The website Canva has loads of free designs that you can use or add elements to your own, I absolutely rely on it!

Is your wedding very complex/large? I'm just wondering how many 'dates' and 'responsibilities' your wedding party have that you need a folder for them?!

I would say that generally, an email or a printout would be sufficient. If your friends are that forgetful, they're likely to lose a big folder anyway.