If you Summon “Armor Exe”, flip it face-down with “Book of Moon”, and flip it face-up with “Book of Taiyou”, it CAN attack because its non-attack effect was reset and because flipping it face-up with “Book of Taiyou” was NOT a Flip Summon.
If “Skill Drain” is active and “Armor Exe” is Summoned, or if “Skill Drain” is activated after “Armor Exe” is Summoned, in both cases “Armor Exe” CAN attack the same turn it was Summoned.
Removing a Spell Counter from “Armor Exe” is a cost.