About number 1, didn't they conclude that the King is where the King's guards were? The entire attack on the castle was based on that assumption. Knov experienced the aura of a King's guard, so they knew the King is in the building. They should have nuked him then and there. I'm pretty sure 10 of those rose bombs would have obliterated the entire compound and surrounding area.

About number 2, will these thematic elements you mentioned be shown in the future? Because up until Netero went suicide bomber on the King, everything was all about Nen abilities.