I still don’t follow the lease question. If you turn in your lease early you still should turn it in to the dealer who you bought it from and negotiate an early lease payoff. Why would you want to involve Tesla with that?
I can answer the question in a general sense as I am very familiar with leasing as I have mentioned in other places.
Its true that, for most car leases, you turn them in to the car maker you leased it from. That is called a lease turn in. Most leases also have an "option to purchase" attached to them. This is the price to buy the car outright. It normally consists of the balance of your lease payments left, whatever residual (balance due on the car after the lease) is left, and any lease end charges / fees assessed.
Depending on what the residual amount is set at, and what the car is actually worth on the open market, its "possible" for the car to be worth more than the residual amount left on it. As a fictitious example, lets say the residual amount (amount balance due to purchase car at end of lease) is 20k. Lets say your payment is 500 a month, and you have 2 payments left. Lets say lease end charges will be 500 (using round numbers for ease of fictitious calculations). Lets say that the manufacturer says this is all you owe, so the full buyout price is 21.5k.
If this car is "worth" (on the open market), say 23k, you have a situation where the car is worth more than what is owed. In such a case, you can just give it back to the dealer (and they will realize this difference), or you can SELL the car to the dealer, or some other dealer. They pay off the car, and pay you any difference in value left.
So, you can either do a lease turn in to a dealer of the car manufacturer, or you can SELL the car to anyone, for any price you want / can get, and pay off the balance on the car and realize any money savings.
Saying all that, it almost NEVER works the way I detailed above. The "normal" way it works, is the car is worth less than its residual, so if you sell it to someone there is a balance due (if you didnt put a large down payment down on a lease which you should never do). If its the same manufacturer that your car is, sometimes there are special lease turn in prices the dealer gets to absorb this negative equity.
There is NEVER a special buy out price for a different car manufacturer (say selling a leased BMW to mercedes or porsche). Its almost always a losing money proposition to sell a leased car to a different car manufacturer. There is almost always negative equity in that transaction. Even if one does not see it (regular car purchases), its normally buried in the price of the NEW car.
So, its normally not a good idea to try to sell a leased car to a dealership that is not the manufacturer of the car. It CAN be sometimes a decent deal to sell the car back to a dealer for the SAME manufacturer, if the "stars align" properly. Takes some calculations, and knowledge of how it works.
Saying ALL that, its fairly clear to me that this OP does not understand how tesla works at all. First, tesla does not have any dealerships as we all know. Second, tesla is not going to pay top dollar for any lease purchase. There will almost certainly be negative equity, unless this OP is used to putting large money down on his leases. That negative equity would be transfered to the tesla.
There is almost NEVER a good excuse for absorbing negative equity near the end of a lease, when one can simply pay the last couple of payments and turn the car in. This OP will almost assuredly not make money selling the lease return to tesla, as tesla has no way to bury the costs in a new car the way traditional dealerships do (with back end factory to dealer cash, or hiding it in other fees, warranty extensions, leather treatments, window etchings, etc charges).
Back to OP.
OP, if you are getting a tesla model 3, you need to cancel your plan to "negotiate the sale price during purchase" as tesla simply doesnt operate that way. You should be turning the car into whatever manufacturer you bought from, and be done with that car, and then buy / lease your tesla. You wont be "negotiating" on a tesla at a "dealership".