Nice, I see you are integrating the script part in the first post. 👍
Oh my god thanks I'm so angry I swear I used the search before I made this and must have missed it.
I added 6 new all_in1 plug & play consoles runned by xavix.cpp driver. They need frameskip = auto. With that, they run well. The list is in "Tutorial: Handheld and Plug & Play systems with MAME" is updated with those six consoles.
I add those plug & play in my gamelist.xml and downloaded images. see : https://drive.google.com/drive/folders/1bfuYF7Ij_dhNc9b8bVCS6I22XiEmP7rv?usp=sharing
For lr-mess, I added a gamelists and images for pockstat and updated svmu with more games.