IMO...
Perfect solution: Marvel Studios get the rights back. They continue making Spider-Man movies with Garfield in TASM universe, but they fix them/make them better. Then after A:IW2, some reality warp happens and Spider-Man moves to MCU universe. If A:IW movies go the Infinity Gauntlet way, there will definitely be some reality warping done.
If it's really the end for TASM/Garfield: don't introduce Spider-Man until after A:IW2. The text above says "2018 release date"... better move it to 2019 after A:IW2. Have it lead the Phase 4 with 2nd Hulk movie.
Perfect solution: Marvel Studios get the rights back. They continue making Spider-Man movies with Garfield in TASM universe, but they fix them/make them better. Then after A:IW2, some reality warp happens and Spider-Man moves to MCU universe. If A:IW movies go the Infinity Gauntlet way, there will definitely be some reality warping done.
If it's really the end for TASM/Garfield: don't introduce Spider-Man until after A:IW2. The text above says "2018 release date"... better move it to 2019 after A:IW2. Have it lead the Phase 4 with 2nd Hulk movie.