>>After doing some searching I understand that when you take the bloodoath as a non orderly evil you get your ethos changed automatically?.

Yes

>>I also seem to understand that it has no effect on your char unless you are possibly an empowerment char which you may need some Immteraction.

If you start as chaotic AND sphere chaos, it can do some wonky stuff. If I remember right, you cannot get your ethos changed via bloodoath as an empowerment char (maybe that was only if you started chaotic though.)

>>If you head down the non orderly route and decide to join the Empire, do you need a PC to oath you instead or is it Imm driven? Will the Imperial recruiter still oath you?

Should be able to get grabbed by a PC or recruiter just fine.

>>Also does being 'wanted' in the past effect any of this?

Nope