This is an abrasive disc, no designed for plastics, will generate heat at the contact surface and melt the vinyl that will stick to it but also generate noxious and corrosive gases from the Poly Vinyl Chloride .
No , get a aluminum blade
Yes, it will go through easily ,but do not force it to avoid crushing the extrusion, wear gloves and keep enough leverage on the part that you hold to maintain control of the cut.
Not sure, you need to check the arbore size.
As long as the arbor dimensions are the same, likely yes. If you have a 12" blade, you will just have to crank the blade up a little further.
Yes, but you will need to make sure your motor on the saw stays dry, so you will not be shocked or electrocuted.
I would not recommend it. This type of blade cuts by abrading, i.e. rubbing it until it gets hot. This will simply melt the siding. I would suggest a fine toothed blade designed for wood over this blade.
You can turn this blade as slow as you want. I have it fitted to my nice DeWalt miter saw, and no concerns. 1/8" steel? No problem.
The label on the blade says 6100 RPM.
A mitre saw might unduly stress and break the blade. A chop saw cuts straight down and a mitre saw can be adjusted to make angled cuts.