mtb, your MLC is dangerous thinking. I know because if you read my threads you'll see I was there too. I had one of the veterans here point out to me that you better hope it isn't a MLC. MLCs are not necessarily temporary. At least not for a long time. MLCs aren't like waywardness, where reality can snap them out of it. MLCs can become the new norm. Waywardness is often times mistaken for a MLC because many of the symptoms are the same. But MLC resolution can take years, where waywardness is usually broken by reality.
Now the temptation here is to say your WW has had a lot of reality so it must be a MLC. Not necessarily. She has had at least two enablers, the uncle and OM, that have kept her from her reality. Also, early on you too were enabling her hoping to nice her back.
The trigger pull is up to you, mtb. However you need to be careful to think that her manipulation is things improving. The way you know that a wayward is over it is by consistently non-wayward behavior over a long period of time. Her silence is scary because she has shown that she is capable of massive slanderous lies. Do not take her silence as a good sign either. Likely she is telling everyone she encounters what she told the few people that told you. Also, she has shown the ability to use many and various tactics to manipulate you. Silence may just be another tactic.
So the question is, are you ready to move on? Or do you want to keep trying to wait her out? Has anything she's done made it so that you don't even want her to come back or are you able to completely forgive her of everything?
Yes there is a lot to think about. No there is nothing saying you have to pull the trigger now.
So give it some more time. See if things continue to moderate. I'd also ask her about the slander next time she reaches out. She should know that her lies have made it back to you. See how he reacts to you confronting that head on.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018