I prepurchased the Heroic Edition of Shadowlands which came with two level boosts (110 and 120). With the level squish, how will these handled? Will they converted to level 50 boosts or will I lose them entirely? I don’t have any desire to use them right now but it’d be nice to have them for later if I want to quickly get an alt going on another server.
We know the 120 will be squished down to level 50, but I haven’t seen any confirmation on what level the 110 will squish to. Not sure if someone else here might have seen anything on that yet.
But they should not disappear on you 
If the table on Wowhead is correct, then 110 should translate to level 45.
This. Also note that based on the formula they are using to squish levels, a 110 boost would be 45, but actually being level 110 is 45.8. Not a huge deal, but if you use the 110 boost now and do nothing else, you should get nearly a full level.
Might also be possible that all boosts will simply become 50. We’ll find out by the end of the month I imagine.
I’m thinking you are correct. Like when they “upgraded” the level 90 boosts to level 100 ones.