My two front tires need to be replaced. Is it OK to replace those two tires or do I need to replace all four tires? If I replace all four can I keep the two good ones as spare tires? My tire size is 195 /70/ 14. Does the brand matter also? Am I better off using all season tires?

You can replace two tires. You can keep any decent tires for spares. I would use seasonal if you live where it snows.
If what you had to replace was one front and one back I would put both the old ones to the front or the back.
I don't have a tire preference so I don't know much about brands.

My two front tires need to be replaced. Is it OK to replace those two tires or do I need to replace all four tires? If I replace all four can I keep the two good ones as spare tires? My tire size is 195 /70/ 14. Does the brand matter also? Am I better off using all season tires?

Well if it is a four wheel drive vehicle I always have just bitten the bullet and gone with a full set. Now if only your two front tires are worn unevenly, you need to see about having your front end aligned. If the front tires are out of alignment, they will be slicker on one side or the other. If it is worn on the sidewalls evenly on both sides, that is a symptom of under inflation. If worn in the center only of the tire evenly around the perimeter of the tire, that is a symptom of over inflation.

Make sure you read this:

https://www.askmehelpdesk.com/cars-trucks/reading-tires-manufacturing-date-236786.html