1. If you're asking if it still has to be the first thing you activate in main phase 1, yes. It is a timing requirement.
2. Yes can be negated by oppression. (At least 80% sure I think, not very sure on this one). Oppression can negate the effect of the special summoning, e.g. stardust from grave, etc. So can negate. The card does not have to be on field.