Hi, I have two questions:

1., If I have for example two developments in zone that has eight damage points now, and my enemy plays a card that removes my two developments, would my zone instantly burn?

2., Can I sacrifice a unit that would leave play by a card effect?

1. Yes

2. Depends on the card effect that would make it leave play, and what effect you want to use to sacrifice it. You can't just sacrifice a unit without a card effect allowing you to do so. If an Action targets the unit and would result in it leaving play, you can respond with an Action that sacrifices it, and the latter will resolve first (the unit will either be sacrificed during the resolution of the effect, or directly as part of paying the cost, if the sacrifice is a cost) before the one that would make it leave play. But you cannot respond to a Forced or Constant effect, so if one of those would make the unit leave play, you'd have to sacrifice it before that effect fires.

Thank you for the reply!

2., There was a situation where I played Judgement of Verena on the opponent and he had a Lobber Crew in play in his Kingdom. The question was that can he sacrifice the Lobber Crew after I played my card but before it is destroyed by the card's effect?

Yeah, that would work.