@Joe T. :
I get your situation. And, yes, sometimes it can be a slippery slope if you make exceptions and cater to every whim of nitpicky tenants. They can get worse and more demanding. When I first started out, I had a tenant like this.
The bad news is your tenant sounds like she might be annoying. The good news is as you continue to landlord you will learn from these situations how to deal with them. It's interesting to see a wide range in how other landlords would deal with a tenant like this.
Personally, I'm like you in that I want to keep things as professional as possible. I don't want to become a tenant's therapist or whipping boy or whatever. I am happy to make repairs and pride myself on offering very nice, well kept homes for tenants, but I like to keep an arm's length with my tenants and not get overly involved with their personal lives. Not because I don't care, but just because I've noticed when I do this, it becomes a bit dramatic, exhausting, annoying and time consuming. Like a tenant soap opera.
In your situation, since she never filled out the move in checklist, I'd head over there (doesn't have to be when her parents are there if that makes you uncomfy) with a checklist in hand, and do a walk through with her before you it gets any later. Go room by room and check off what is ok and any existing issues, date it and both of you sign it. If you see anything that needs swift attention, you can set up a time to repair. So now that's done.
Then give her written repair request forms. In person. Slap your address and a postage stamp on some envelopes if necessary. Explain to her that you need a paper trail of some kind with regards to repairs that are non emergent, and she can fill these out and send them back to you and you will go from there. The forms should say what the repair request is for and if you feel it's a cosmetic issue that is not worth fixing, just check "no" on repair request form with a brief explanation of why you won't be repainting the place in her favorite color or adding windchimes or whatver the deal is and send it back.
If the place is in working order and she dosent submit request forms for the cosmetic stuff, fine. If she does, you will have a paper trail that you want with descriptions of the requested repairs and why you turned them down.
With the lost key, I have something in my lease that says I call a locksmith and the charge goes to them if this happ Ns. This was after I had a tenant call me after bars closed needing to get in and I was a new parent. It happened constantly and was exhausting. I don't always adhere to it, I go by the situation. A one time thing where someone's purse was stolen? I go unlock. A chronic key loser that's calling me at 2 AM a couple times a week? I enforce it. Once they realize they will have to pay the locksmith, they keep better tabs on their keys!
Tenants can be a challenge, but they are also valuable learning experiences. Next time you will know to do a walkthrough immediately with the tenant, etc. You learn as you go. Good luck!
-M