Let's Go question

They retain the same level when transferred over. A level 20 in Go will be a level 20 in Let's Go.

IVs also remain the same to some degree. Stamina is directly translated to HP, while Attack and Defense retain their values while being duplicated for both Physical and Special. The Speed stat, since it doesn't exist in PoGo, is rolled randomly.

They will be the same level 20. Don't worry about that. Low level pokemon grow quickly in Let's Go. The bigger issue is the trash catch rate for pokemon in Go Park. Because of those two factors, when possible I have been sending mostly low level pokemon.