This is a great question. I have been doing this since mid-2016 in my owner-occupied residence with up to 3 roommates living upstairs, I live in the basement but share the common area (kitchen) with the rest of the house.
1) Yes, use a lease. I customize it for each room and other parameters. I also don't allow my tenants to enter the basement without prior permission. I use EZ Landlord Forms dot com.
2) I have only done tenant referrals by word of mouth so far. I have been lucky in that regard and have yet to actually advertise. This gives me piece of mind as the referrals usually come from friends, coworkers, and the other tenants. That being said, I take care to treat everyone the same. My situation is a bit different, but if I was to rent out to a random person from Craiglist, I would vet them to the nines.
3) Yes. Unclear on common area damage. It hasn't happened yet. The micro-cameras are a little creepy IMO.
4) Let tenants sort this stuff out. You have enough on your plate and can't predict the future. Things change so much, it's almost impossible.
5) I only do word of mouth and ask for guys only. I live with them in the same space so the laws technically don't apply to me since they are my "roommates".
Bonus-
One issue I have run into for those out there who rent rooms and owner-occupy is the insurance issue. I notified my insurance company after the fact about roommates and they told me I could be dropped from my insurance. This scared me and I haven't found a solution yet. The one thing I have done is to require renter's insurance though. This gives the tenant liability coverage and CMA in the process. So if something were to happen to them, they could go through their rental insurance company. Also, I make then sign a waiver of liability.
Here is the post I made. I still have yet to find an answer, unless renter's insurance is the answer...
https://www.biggerpockets.com/forums/52/topics/497275-insurance-for-roommate-tenants-in-owner-occupied-sfh-washington-d
Lastly, I am unsure of if you need this, since it sounds like your basement is a seperate unit, but you may need a Basic Business License. Finally, I did attempt to contact an attorney to touch base on my specific situation. They informed me that I needed to register with the city. I am working to figure this out. Please feel free to message me with other questions. I'm still learning myself on these issues.