2000 Chevy Camaro strange noises and windows

I recently bought a 2000 Camaro v-6 coupe for a fun/weekend second car, hoping it won't need lots of costly repairs. It seems to be in good condition overall, the only problem I noted was tough steering, checked the ps reservoir, was below the dipstick, filled it (perhaps a bit over), haven't seen any leaks. My questions are about 3 strange noises the car is making:

1) Drove it in heavy traffic for first time, about 40 minutes each way. On return trip, heard strange wavering whistling noise. At home, popped hood while idling, whistling continued, varying in pitch and volume while rpm was still at idle. Looked online, got feedback for belts, egr/vaccum hoses, and the air pump. Have yet to remove air pump fuse to verify if it is this. What could it be? How much to repair/replace air pump? Is it a problem to pull fuse and leave air pump deactivated?

2) Engine makes slight ticking noise at start up, seems to go away soon- can't hear it on the road or at stop lights. Egr hose, or what?

3) What appears to be transmission noise is present whenever driving as a moderate to high-pitched hum that changes with the motor's rpm. Checked trans fluid, level fine, also know that trans serviced at 41k miles. Heard same noise when listening to a v6 camaro on a you-tube clip. Is this intrinsic to the 3800 engine/power train, or is there cause for worry?

Last question is on reluctant pass side power window- goes up part way, has to rest repeatedly, a struggle to get it all the way up. Has the same problem from either door switch. Can I replace just the pw motor, or will I need to do the regulator too?

Looking for anything I can do on my own, or advice to the contrary as needed. Thanks for your help!