Hi,
Is it possible to install both Jup-8 V3 and V4 on the same computer (M1 Mac Mini)?
Yes. They are different applications and can installed alongside eachother. I have not uninstalled my V3 to install V4. V3 is not being uninstalled automaticly, so you must have it installed, unless you have uninstalled it yourself.
would Analog Lab V see Jup-8 presets?
Yes it will also see the V3 presets if you check "Include Legacy Sounds" in ALVs menu in the top left of the application.
But the V3 presets will use the V3 engine. They can't be used in JUP-8 V4 engine. Perhaps Arturia will create a preset converter, but as V4 is changed much, then the presets can't be excactly the same.