These are all great questions.
@compmom I’m not sure if UG VP is something to avoid. I do know that there are more programs than ever and so many singers who really may never work professionally are being accepted into them. When it comes to auditioning for MM programs and getting the funding needed ( I heard it said somewhere on here that if you’re paying for grad school it’s a good gauge of where you stand in the talent pool. although don’t quote me 
I think you need to be a smart singer first and foremost. Perhaos an UG degree in a language, with a huge amount of theory and expert sight singing skills combined with a wonderful teacher might be enough for a rare & stellar talent to then go on to a top tier MM program. Though, I’m not sure they would also have the repitoire, coaching, movement, dance, acting etc. that a singer really needs to compete and perform professionally. So while it does take the voice time to mature there are so many other things that a VP student needs to be working on while they protect, train and nurture their young voices.