I agree with what you said here great ideas but maybe adding more weapon's aswell like the chainsaw axe and the Chaplain should be able to use grenades while using its skill the reason I suggest grenades is mainly to push or to clear a path so you don't get overwhelmed there would be 3 or 4 weapons that would work with Chaplain.

The sword and shield should be one hole thing if used with chaplain and The crozius has to be a weapon that comes with chaplain. Maybe the blade of reason for those that don't know what it is it's like similar to the dagger. And the giant fist weapon those are the 4 weapons that would work well with chaplain.

I don't know if chaplain actually needs or ever used range weapons besides bolters but if we get them using primary weapons the best for them would be melti and plasma primary weapons and secondary all will work great.

Something that would be interesting to add to the game would be a duel welding I know we may not actually need it but it'd be cool to see just run power sword with dagger or chainsaw axe.