I'm going to assume the overall enhance would be worth be giving a creature +2 | +2, based on the varying worth of the improved cards. Your interpretation may vary.
+2 | +2 boost would be be worth 2
, based on blessing.
1.5 + 1.5 (Elemental Cost) = (Other Cost)
1.5 + 1.5 (2) = 4.5 ≈ 5
As for Downgrade, it's has more of an offensive focus, but on average I'd think it gives a -2 | -2 debuff, similar to upgrade, which I think would be also worth 2
. Upgrades usually result in a -1 or -2 cost, so it could cost 3.5 or 2.5 , which rounds to 4-3 quantum respectively.