Sadly, Resculpt and Mirage Mirror dont hold significant secondary market values, but this Secret Lair is easily worth the buy either way
The Blue clearly makes the populate mechanic better because you have better targets by virtue of Blue having the easiest time turning creatures into tokens, but I submit that Blue makes the rest of the deck better
In Legacy, its slotting into similar Mardu Energy decks as it is in Modern
Shriekmaw Shriekmaw is a longtime favorite of mine, especially in Commander
Klothys, God of Destiny may be the best reason to seriously explore this idea
The first ability of Ral, Leyline Prodigy will count any instant and sorcery spells you've cast that turn, including ones that were countered, didn't resolve for other reasons, or are still on the stack