I'd say option 3. Personally, I don't care if random websites get my IP among a list of hundreds of others, and if someone wants to keep their IP hidden from strangers, they should be using a VPN before browsing the net anyways. It'd also be nice not to have to open another instance when I come to a post with a broken image that I want to see, but that's not hugely important to me.
If it were an instance specifically for privacy enthusiasts, that'd be a different story, but this is a general-purpose instance, and option 3 seems to be what's best for both general users and the server itself.
Sir! Excuse me, sir!