First of all, excuse my English and my low ratio to make this answer a comment.
Secondly, I have always had the same doubt about how oil mixture affects 2stroke engine performance, and (I know it's not the same but...) few months ago I found an article wich is very interesting, talking about oil in chainsaws
After you change the oil and filter and refill the oil pan, you have a few seconds before the oil fills the filter and oil passages and begins lubricating the engine again. During that brief period you're relying on the residual oil film that clings to the various surfaces in the engine to provide protection.
How long does that protection last? Generally ...
Some damage is likely, but not quantifiable.
Some engines have been run for 10 minutes because they wanted to destroy the engine and it took longer.
You probably reduced the life span of the engine or it might make a different noise soon.
If it is now filled with oil and running then use it, not much else to do. You could strip it and rebuld it but as it is ...
You poured antifreeze into your oil gallery ... you need to drain and fill will fresh oil. If you haven't ran it, you can possibly put the vehicle on level ground then pop your oil drain plug out for a short period of time, but long enough to drain the coolant out of it. You will drain some of the oil in the process, so be prepared to add some back in to top ...