Campaign Level 5 - Overworld Gateways and Templars

I've just played Level 5 of the original campaign ("The Rear Guard") again, and decided to try a different strategy to what the game probably expects. I started the Shifting Bonds ritual (you have to in order to progress at all), then immediately cancelled it and set about building up my dungeon intending to take out all the Overworld Gateways and kill the enemy leader before completing the ritual. I found three problems with this:

1. The objective does not clear from the top-right of the UI once all the Overworld Gateways are destroyed (although it does update correctly to show the number of gateways remaining).
2. I started the ritual after wiping the map clean of enemies, including the enemy leader. However, at various points in the ritual's progress, the enemy leader's lines of dialogue were still playing as though he were still alive.
3. At one point during the ritual's progress (I can't say exactly when as I had a huge army of high-level cultists at this point so it went extremely quickly) one of the Overworld Gateways (again, not sure which but at a guess I'd say it was most likely the centre-left one) spawned a party of low-level dwarves to attack my dungeon, even though they had all been destroyed.

One other (unrelated) issue is that the first few waves that attack your dungeon each include a Templar. Since every other enemy on this level is some sort of dwarf I'm guessing this is a mistake.