Personally, I would wait until after the deal closes, then personally go to each neighbor (not call, go sit down) and "introduce" yourself as the new neighbor. Doesn't matter if you already know them or not. Be honest, tell them your plans, discuss any discrepencies on the survey, discuss anything they are using the land for, your liability concerns if they are, ask if you can work something out (yearling hunting lease if you don't mind, hunting buddies, whatever)...You may find some who are peeved you took the land without them knowing it, they wanted to buy it...appologize, say you didn't know their situation, you were offered the land (or offered to buy), deal was made, you weren't aware of other situations...take the high road, if they are mad, they will be mad. Be humble, be nice, don't be confrontational, but make sure they know you own it. Leave all your contact info if they need anything, offer to help. And I agree, good fences make good neighbors! Even a 2 strand barbless wire fence with posts 20 feet on center, ON the property line is better than "that tree line"...
The one lady using your land for a driveway, tell her your lawyer advises you to get the permission to use it in writing, write a simple lease for 50 years at $1 per year, pay first year, balance payable at the end of the lease in one lump sum if no changes to lease are made, lease is broken at change of property ownership, lease can be broken by any party with X months notice...and have it recorded at the courthouse, then there will never be an adverse possesion case. Chances are the property won't stay in the same hands for 50 years, the lease will be broken and no additional payment required, but you will be covered from adverse possesion. If it does go 49 years, give notice before it's up, with the offer of a new lease for 50 years at $1.01 per year, same terms...
And congrats, looks like a great piece of land! Trees and an area like that are unheard of in my area, if there are trees on a piece of land, someone planted each and every tree and watered them until established...