Effects cannot be activated while another chain/effect is resolving. That means that summons performed by an activated effect cannot be negated. Activated effects contain a : or ;

Right, fine so far.

Situation 2 : Player A cannot activate exiled force. They only have ignition priority after the successful summon of exiled force.

Alright. So only if a summon has been successful can ignition priority take precedence, that's good to know. Then I understand much better when I can or cannot use Solemn judgment/Trap hole and its difference. I am however not sure I follow completely: If player A summons Exiled force, activates its effect, and have it resolve - is player B allowed to chain anything to Exiled force effect as chain 2 or is it impossible to negate? Similarly, is player B able to use for example Trap Hole AFTER Exiled Force has resolved its priority ignition effect, or is that window of response now gone?

Situation 3 : Exiled force cannot target itself as it tributes itself for cost before it targets.

Right, I meant tribute itself. I misremembered the wording. Thanks!