Glad to hear you have power back for the Christmas!
This uses MZ3D 8.2.2 and I think the dynamic lighting combined with the day/night cycle is the reason for bad performance. For me adding the dynamic lighting caused a huge performance drop and stuttering.
I've been trying to optimize it (recently today by spending 5 hours tweaking and testing it), but it's a tricky one. Without dynamic lighting I get huge improvement in frame rate.
I hope I will find a way to optimize better, but so far I haven't been very lucky. I have even considered replacing it with basic lighting. We'll just have to wait and see can I get it to work properly.
But I will continue working on it after holidays.
I would be interested to test your mouse plugin and see if it would improve the performance.
Merry Christmas!