>  - how can one identify legit accounts of popular Nostr users? Right now I'm going based on highest follower count among the various impersonator accounts 

NIP-05. Also called Vanity Addresses. 

On my profile you see below my name mananguri@onlynostr.club.  That's a NIP-05 address.  Anyone can call themselves Mananguri, but only I have access to the mananguri@onlynostr.club registration PIN.

I can also use that NIP-05 address as my lightning wallet address too.  You just point the address to your own lightning wallet.  It's really simple to setup. Check it out.  

onlynostr.club