I think most people on here will see this as abuse. Same PNR - no problem (although this isn't a clearly documented benefit). Same flight - I don't have an issue with that, but I think some people may have. Different flight? Well, you're pushing your luck here - it's not like the agent can process you at the same time, is it?

Re. lounge access, make sure you find the rules that float around here and take a copy with you, just in case you get grief from the dragons