yes that is the stock tire on mine.
yes
P235/75/R15
215/ 65/R15 were on my last Windstar, they worked well.
Yes.
235/70/r15
On my 1995 Ford Explorer XLT with the 235 / 75 / R15 tires I have a revised sticker on the end of the drivers door that shows ( 30 PSI )
Not on a Windstar. Ford allows for two tire sizes for most models, the 205-70-R15, or the optional 215-70-R15. Changing tire size that drastically could lead to clearance interference, and speedometer/odometer false readings
yes You can but check to see if the revolutions are the same so the speedometer reads correctly.
235/75 R15
235/75 R15
235 x 75 R15