Disc Feeding / Ejecting Gets Stuck

Problem I'm having

Discs (games and blu-rays) both play properly, but the feeding / eject mechanism only sorta works.

• Feeding: I have to push the disc 80% of the way in to get it to feed. I can hear the motor before I get to that point, but it does not feed until I put it that far in.
• Ejecting: It only ejects a little bit out of the console and I have to pull it out ht rest of the way. Similarly, I can hear the motor continue to turn after the disc is ejected.

Guides I've found so far

• https://www.youtube.com/watch?v=nsIdtW35...: for one that is not feeding at all, fixed by just taking apart and putting back together
• https://www.youtube.com/watch?v=Qe9jaQS-...: disc not feeding at all, fixed by taking apart and plugging in drive (also a software update). I can't imagine this is a software issue.
• https://www.youtube.com/watch?v=NDuvwJRF...: disc not feeding at all, clips were not put in properly
• PlayStation 3 Slim: there is a guide for replacing the blu ray laser, which doesn't seem to be the problem. There is another for replacing the whole blu-ray drive, which seems like overkill for now.

My questions

I'll probably try taking the system apart and getting to the feeding mechanism to see if I can find anything wrong. I'll also probably dust the system out just in case. But:

1. Is there anything else (common parts to check, weird gotchas) I should be on the lookout for?
2. Is there a known cause of this issue (partially feeding / ejecting discs) or similar issues?
3. If the drive does have a broken part, do I have to replace the whole blu-ray drive or can I replace the small component? I don't see any smaller parts, but I'm also new to the repair scene and don't know where / what to search for.
4. If I want to clean and lubricate the mechanism, what tools / cleaners do I need? Just isopropyl?