Just a bit of insight. I live near UMD in Duluth, MN. Sprint's signal is clearly much 'dirtier' with a 1.0 SNR compared to T-Mobile's 20.4 SNR. I don't have a screenshot from the same time, but I get about a 22 to 29 SNR with T. I know that AT&T uses RRU's but I'm not too sure about Sprint or T-Mobile. Also, I didn't even know they had L2500 where I live, but I force checked it on my Samsung S7 (AT&T).
I think they would basically buy Sprint's owned tower locations, and Sprint would lease them back at some rate. The lease could be well below market value. This would give Sprint a cash infusion without SoftBank directly investing and triggering them to buy the remaining shares
I'm not sure how many locations Sprint owns. Or perhaps they'll just take over Sprint's lease and then sublet it back to Sprint at a discount.