A spell's mana value is always based on that spell's mana cost, not any additional costs you pay
Otherworldly Gaze If you count Surveil spells as self-mill (and I do, given how rarely you see triggers that care exactly how cards end up getting from your library to the graveyard), then Otherworldly Gaze is as good a choice as any for the most consistent, efficient, no-bells-and-whistles version of the effect
If you really want to play it, Juzm Djinn is a rather unremarkable 4-cost 5/5 beater, though it is worth mentioning that it was the first 4-cost 5/5
Ichikawa highlighted the four-year development period of the Magic and Final Fantasy collaboration, during which both teams poured all our love and attention into it, believing in the best possible future
Rinoa wants you to build a large board of creatures and token creatures