Is this parking lot viable for overnight parking & sleeping in vehicle?

I dunnogh?

Yes u can

Looked good to me. It's clean but I didn't check the light poles

Make sure and ask as many resources and be 100% sure to avoid tickets and towing

Speak with a manager to get approval. Usually it's ok and they will tell you where they prefer you parking.

Yes & No...trucks maybe ok but I would not do it.

Yes just watch out for the lady in the van with writing all over it. She lives in her van in the parking lot.

Nothing is posted stating that you can not so that makes it legal

Yes