Yes
no you cannot
no you cannot
no you cannot
NO, the last digits (R15 and R16) refer to the wheel (rim) size. If you change wheels you can install the 16" tires. A much better swap would be to install 205/65-16. The parameters except width will be almost identical to the 205/70-15 tire/wheel combination. Your speedometer will read 59.5 at a true 60 mph.
No you can not. say for example 265 70 R16 the height of the tire from the rim to outside of tire is 70% of the 265. you can use a calculator to find what size of tire you can use other wise your speedometer will be out
That will depend on the application. The sidewall of the tire will list the maximum safe operating pressure. The owners manual of the vehicle will list the recommenced pressure for use on the vehicle.
You can use 205 but your speedometer which will be off. Handling ride and steering will also be adversely affected. Stick with the original equipment size. Plus, you will need 15 inch rims instead of 16 inch. I actually misread your question and did not notice you were wanting to install a 15" tire. In that case you should install a 235/60-15 tire on 15" wheels which is an almost perfect swap and will work well.
Although this is not a great swap it is acceptable. Know that your speedometer will read 58.3 at a true 60 mph. You will also have less pulling power. If you wish to go to a 70 series tire then a 205/70-16 is a much better swap. You speedometer will read 59.5 at a true 60 mph. Power will be effected very little.
Lots of vehicles use this size.
No you can not. say for example 265 70 R16 the height of the tire from the rim to outside of tire is 70% of the 265. you can use a calculator to find what size of tire you can use other wise your speedometer will be out
Yes you can
If you are using the same wheels, no. The last number is the size of the wheel, and obviously a 15 inch tire will not fit on a 16 inch wheel