bought a little project 1994 wrx jdm but still unsure about headgasket problems?

took it for proper little test friday night rans brilliant fastest car i have driven scared me if im honest. brought it home checked everything noticed in the little n/s tank that bubbles were appearing

we lost water so filled up.

heared a whistle from by the aircon pump so could be split somewhere??

could the system still have a airlock, as these systems are known for it.

basically does anyone think the headgasket is gone or do i have a leak somewhere.

cheers.