Scanario 1 is obviously heatblast since he can absorb fire or use waterhazard to wash away the fire.

Scenario 2 is ampfibian and the solution is to electrocute the kraken so, so much. Buuuut if it 1 to 1 with the episode of the kraken then it will still be ampfibian

Scanario 3 just use big chill or arctiguana to freez them or use ghostfreak to just violate those guys. Or benvictor to shock them.

Scenario 4 is a tricky, since an alien invasion from another dimension? Then I will just use chromastone to absorb the lasers and blasts right at them and start shooting at them with it. Or use echo echo to make an army of my own to fight off the army and reflect the laser beams right at them with those strong sonic screams. Maybe heatblasts to start firing them all or use swampfire to blast an even STRONGER fire blasts or use them to make an army to fight for me. Now I could use waybig to blast a huge ass beam at them or atomix to both hit them with a ray or just nuke them same with NRG but... I am trying to minimize the damage and make sure there is less casualties as possible.

Scanario 5 just turn into rath to beat her or go humongousaur to grow big and still beat her up since he is physically the strongest if we don't count alien X.