If you search you will see a lot of discussion on this "offer" by Musk and why no one will take it up.
If you want supercharger network, you will have to buy a Tesla.
the more the merrier, (standards that is
at least LEAF 2, GM Bolt and Tesla 3 will not be clones of each other, even if they have some MSRP overlap.
Personally I expect those who have reserved a Tesla 3 will need to finalize ordering quickly if they want the $35,000 version. I don't think the entry level Tesla will be generally available with federal tax credit, but the LEAF 2 and GM Bolt will. I also predict the LEAF 2 to have about 250 miles EPA (wild wild rumor, but LEAF 2 should have lower aero cross section than Bolt, even if the drag co-eff is the same). I expect demand for higher trim T3 to be sufficient that Tesla effectively drops the supply of T3 with less than LEAF 2 / Bolt range.
Base T3 with a 'reasonable' delivery could be $40,000 and miss the tax rebate
LEAF/Bolt with average discount could be $30,000 and still get the tax rebate (so thats like $23k)
so for 'comparable' vehicles the lease rates for these will be wildly different. perhaps 1/2.
I don't expect fed rebate to last beyond when both Tesla and GM have used up their allotment.
The clock will start.