Second owner, 2008 Aveo5, 44k Miles. Questions and concerns.

I just recently purchased a used Chevy Aveo5 LS M/T with 44k miles and some change (currently 45k). I have become aware of some issues that I can't seem to live with. If anyone could help, it would be greatly appreciated. The issues that i'm concerned with are:

1. When cold starting, every 30 seconds or so, there is a constant ticking from the engine accompanied by by 4-5 backfires. Goes away noticeably after car warms up.
2. Oil in the spark plug well (valve cover gasket, just making sure)
3. loud injector ticking noise.
4. When traveling in gear at speed and engaging the clutch will result in less than normal idle rpm, then recovers to normal idle rpm.
5. The electrical load from turning on the headlights, plugging in a phone charger or turning on the heat will cause engine rpm's to drop, then recovers.
6. higher RPM's will produce a harsh buzzing from the cabin (ball bearings swirling in a mason jar). Sounds like something loose and vibrating...giggity
7. When the heater is on defrost, there is a whirring sound coming from the blower (less noticeable when the blower has warmed up.)
8. The car is blown around significantly on the highway. Constant corrections are needed at 70 mph.

I bought the car with EXCELLENT service history. Every scheduled maintenance has been recorded by 1 dealership. I will continue the tradition and record all maintenance/services performed by me or a certified technician.

Thank you.

You said nothing about what diagnosis/maintenance you've done. Examining the spark plugs is the automatic first step, but I would hope you've done at least that much. List the things you've already done, in order to avoid everyone wasting their time.

i saw your live data thread, came here instead.

1-2.
If you have oil in the spark plug well, and changed the plugs (I only ran the OEM style coppers) did you change the wires? coil pack? based on the oil problem, wires would probably sold the misfire condition.
3.
injectors are loud, yes. sounds like a sewing machine even when new. You could try some fuel additive, nothing crazy or you will get more issues.
4,5. Its a small car with a small engine. Small alternator. The idle fuel is probably more fuel than is being applied under cruise. The o2 needs time to adjust, if it is consistent and not stalling it is probably normal. The small engine has a small alternator, thats why the lights dim etc at idle. The battery acts like a capacitor to even electrical flow. If the car has been sitting as you say, the battery might be weak, and need eventual replacement. IT might also get used to working again, or be the wrong battery for the car (TOO SMALL, TOO big is typically ok as long as the alternator can charge it).
6. This could be a lot of things, does it also happen in neutral? if it is only when moving, i would look to wheels, bearings, axles, etc. IF the noise is consistent. Most bearing noises are from spinning parts, so check the belt driven items as well.
7. thats from sitting. you can pull the cabin filter and clean the fan, there might be something in there. put some lithium grease on the fan shaft/motor
8. my favorite. LOWER IT!