You do not want to go to a smaller overall diameter tire as it will adversely effect your speedometer, and performance. You can however go to a 75 series tire which will not change overall diameter. A 215/75-16 will work just fine.
That's a much smaller tire, you may want to think very carefully about that. I certainly would not.
P235/50r17
2010 ford edge
P235 75R 15
Most tires these days are of good quality. If you want a good brand try Michelin. P235 tires aren't terribly hard to find, either.
It means it is a tire for a passenger car and tread is 235mm wide.
Many tire companies make that size.
There are multiple companies that manufacture tires with model number P235 70R16. These include: BF Goodrich, Bridgestone, Continental, Cooper, Definity, Falken, Firestone, Futura, and Goodyear, to name a few.
Should be P235/70 R15.
1986 Rolls Royce Silver Spur
P235/65R17 for both front and rear tires.
It should take p235/75/r15