Anyways, we did not find this out until the contractor had gone back to do some work that the buyers had requested as a part of the offer to purchase, and by then the damage had already been done.

I also put door stoppers on all of the doors to prevent the walls from getting damaged.

What are my legal obligations in terms of sending him notice on not getting his deposit back either as place was not cleaned, major carpet damage done, damage done to trim, trash left etc....?

If you have a tough occupant, I am less worried about the time it takes to get them out than the damage they may do while they are in the pending getting kicked out.Best practices: find an agent who works the foreclosure circuit and knows how to assess the property in terms of it's renovated value versus upset value and potential first bid price.

for selling/flipping I'd leave the trees,  But for buy and hold trees on the property can be future maintenance, like gutter cleaning, or damage like trees falling on house.

How much should I charge for deterioration of the appliances and the damage to my pool deck?  

Is he saying the charges are unreasonable, that the damage doesn't exist, that he should be responsible for the damage?

Make sure to pay it back / set aside the $$ for the security deposits asap, since you will owe the full security deposit - any home damages to the tenant within 14-30 days of move-out, whatever your lease says.Good luck and let us know how it goes.

I'm thinking of asking my tenants to end the lease early so that we can get in to do all the restoration.

I imagine that's a strategy to collect more rent, apply that to the missing deposit then after you have their deposit covered, you can pocket the rest and if they do no damage then you only have to legally return $300.