If an investor signed an NDA and asks for terms of previous investments but not issued term sheet yet - is it a good idea to provide details of previous SAFEs like CAP?

Ask why they needed it. They may wish to know how the valuation rose and/or to assess how many additional shares will be issued and dilute existing cap table. You could answer those questions without sharing too much.

A company got an offer to invest on a SAFE w/ a Term Sheet asking for a subscription agreement. What is a subscription agreement? Are there red flags re: agreeing to something like this?

Our current stock option pool is @ 10%, distributed as I see fit. At Seed, it was fully distributed--but now, I want to use 3% for key hires and 7% for myself. However, a board member thinks founder top-up only occurs after Series A. Does this make sense?