Is it possible to defeat 1000 Archangels with just one Imp?

b) catapult turn. We block the demon with a force field (3 cells; the force field blocks the demon so that the archangels have no room to attack!!!). The archangels destroy the catapult – it's not a problem; the force field lasts for 3 turns.

Are you even aware of how a force field behaves on uneven terrain? With zero magic power? And so on.
You describe everything in such detail, but do you even understand that half of your conditions are just silly complications – everything is much simpler, why this approach? Even reading your post is tiring because of the amount of unnecessary information!

Besides, a force field lasts for 2 turns, not 3! If it lasted for 3 turns, this spell would undoubtedly be one of the best in Heroes 3 and would put some higher-level spells in their place.