More of a 'General' question
Power/Precision does not directly affect condition damage no, however some weapon sigils and trait effects will let you inflict conditions upon critical hits.
For the runes I don’t believe the other four runs do anything at all. Think of it this way, the first rune applies the first effect of the rune while the second applies the second effect and not the first. So once you have those two further runes do nothing. If you want to stack a specific stat on armor a more cost effective option is to use gems found from gathering as they do stack their effects.
Thanks for the info — let’s say I pick up a few gems. I should be able to replace the runes that I’ve put into armor? (Is it as simple as 2x click and drop it over?)