Is it possible to use Sonar's plugins in Ableton? I have copied them to a vst folder but it doesn't look like Ableton recognizes them. Does Sonar allow its plugins (boost11, channel tools, mulitband compressor, etc.) to be used in other DAWs or only in Sonar?

It depends, Some of Sonars Plug ins are what are called Registered and only work when registered with Sonar. The other part is there are different types of plug ins and might be Abelton does not support them all. Is this the free version that came with a Scarlett interface per chance? Just curious as I haven't installed mine yet. 
 
I do know that Boost11 , Cakewalk and Sonitus efxs work for me in Wave Lab, but LP64 efxs show, but won't load.