I would definitely clean the tank fully, just to be safe. Could you use a bucket as a temporary home for the otos as Rose has done? Or go out and get a small tank with an under-gravel filter for temporary use? Of course, then you go back to needing to cycle the tank......
Maybe, if the otos don't show any symptoms after a few days or weeks, you could
acclimate Lilex into the tank as it is, with maybe a partial
water change. Sorry, I really don't know for sure, but would love to help if I could.
(by the way..... I don't think it is too soon. When Dante passed, I couldn't stand to see his tank standing there without the presence of a
betta. Just be careful that the move doesn't stress out Lilex.)
S.