If a shaman summons a hearth spirit at the targets appartment on Tuesday, gathers some intel, then dismisses it, does he get the same spirit when he and his team reenter at a later date and he summons a hearth spirit to conceal his team?

Canon pretty much leaves it up to each individual GM, but that's the way it happens in my games.

What is if two shamans summon a spirit at the same time, one to conceal the first team, one to keep watch for the second team..

Maybe, maybe not. The rules imply either can happen.

[edit] too slow [/edit]