Hi, I recently found a solution to this. If you want to transfer an animation, there are two methods:
For the entire animation:
Go to file and export rigs. Copy this animation and paste it into another rigs AnimSaves model
To add on to an animation/splice together:
-After exporting rigs ^ go under the animation and find all the key frames. To transfer specific keyframes (ie. copy and paste through different animations), locate the time stamps of the keyframes you want to transfer.
If it is over a duration and not just a scene/1 frame, I assume you would get the chunk that covers what you want to transfer. Important: as to not conflict with the animation, the keyframes must be set to a value greater than the duration of the animation in the time attribute.
Copy these, and paste these keyframes into the animation of the dummy. Once you boot up moon animator, the keyframes of the copied animation will appear in the animation you put them in.
Disclaimer: I have just recently figured this out and I have only tested it/used it for specific keyframes/poses. I am active and available to help out potentially for issues and troubleshooting.
Edit: EASIER SPLICE: First have the animation published, then go to file, import, roblox, select your published animation, and select the paste option. Boom, easy splice.