Yes, you can
205/65-r15 or 195/70-r14
You want to have 15" rims on 98 Grand Am. Typically common are 195/65/R15
Yes, but your speedometer will be 1.35 mph off.
No
Yes, you can use a replacement tire of 175-65-r15 for a 195-55-r15 rim.
Yes, they can
Of course you can, but it is not advisable. Your speedometer will read 58.6 at a true 60 mph. Stick with the OEM size.
Yes, you can
Can you replace 205/65/R15 with 205/75/R15
Yes, but your speedometer will not be accurate and performance and mileage will be effected.
The aspect ratio is different, in this case the -65 is a little rounder in cross section.