quick answers-
its not a random creature like fate egg, it stays a weeping angel with set (really good, relatively) stats, the word "random" was not used in the text.
when cloak is removed, i think the most appropriate response is for it to instantly become a permanent again. in the event that all permanent slots are somehow filled up (rarity, but i suppose a bad deck could manage this), the angel will go poof, and you will have nobody to blame but yourself.