There's a limit of 100.

https://domains.google/learn/how-to-use-email-forwarding/

Yes, but you have to manually set up each account (eg. name1@example com) you want to send mail from to verify that you own the account.

Would it work for others in my family, without me being able to read all their emails?

Yes, each email alias can be set to forward messages to a different address.