TLDR: Don't focus on the giving of rep, focus on signalling to the editor whether their action was useful/helpful or not.
You are focusing on the wrong thing. Don't focus on the giving of rep (you only give rep when you award a bounty), focus on the edit.
The first thing to do is to decide is this edit good or not. To see if it is a good edit, lets looks at ...
What is the appropriate action for editing an answer that was rejected by the community?
If you have full editing privileges, you can perform the edit (or a better version of the edit!) yourself. But if you're unsure if it's the right thing to do, raising it on meta like you have is also a good choice.
For non-obvious spam links (like the Xfire link became)...
No, such an option does not exist. Once you finished reviewing an item, you cannot change your decision. Don't worry, mistakes like this happen; that's one of the reasons two approvals/rejections are necessary for a final verdict on the edit.
The number of reviews are no longer shown, so this bug is no longer apparent. Instead, we have grey and red notification dots to indicate pending reviews:
When the queues start to get busy, a red notification dot will be shown on the top bar as well: