Yes as long as you keep the overall diameter the same. For instance you would replace a 185/75-15 tire with a 215/65-15 tire which would keep your overall diameter almost the same. Click the link to calculate what size tire to go with.
No, your speedometer will be off and power and fuel mileage will be adversely effected.
Yes, you can, as long as both tires on an axle are same
Yes, you can.
You can switch to a 215/50-15 or 175/60-15 if you can find any tires in these sizes. Other optional tires which are acceptable are 205/50-15 and 185/60-15 which you can find. My advice is to stick with the OEM size.
No, there is a 3.15% difference in overall diameter. This will cause your speedometer to be off 2 mph.
Yes this is an acceptable swap.
No, how would they fit the rim.
That is a very close swap, so yes.
If there is enough clearance for the wider tire, yes.
NO, the rim size is incorrect.
Yes, you can
yes