"Will these two cross pollinate?"

No

Resin

Thank you! Yippeee! That means I can have them in the same area & not have to dedicate another area for nut trees!
Planning on some hickory trees too, but wanted them in a different area anyway!

I would plant them at least 20 feet apart. They can get really large. My neighbor has a carparthian walnut that is proabably 70 feet tall and 3 feet in diameter.

Certainly no closer than 20 ft - in 'orchard' settings, we shoot for mature spacing of 40-50 ft. You can plant closer and remove some as their canopies begin to crowd.
Your 'volunteer' pecans are, as you've indicated, just seedlings, not named varieties. Nut quality, when they reach bearing age, may be so-so - or could be excellent.

Check with the UGA extension pecan folks - they'll likely also be able to recommend Persian/Carpathian walnut varieties suitable for your area - if there are any. You may not necessarily need the cold-hardiness/late-blooming traits of the Carpathians in zone 8.

I'm not so much concerned with the "quality" of the pecans as I'm only interested in them for my own use. I have 10 trees in one area and all are at least 20' apart...we pulled/cut all the others so these wouldn't be crowded. They were probably from Stuart nuts so we shall see! Neighbor still has fully mature stuarts close by so who knows what I will get!
Our extension service knows NOTHING about Carpathians! They aren't all that knowledgable about pecans...they are more geared for field crops like cotton, peanuts, corn & veggies like cabbage, egg plant, peppers, tomatoes, squash & melons. They first thought I was talking about BLACK walnuts when I asked! ((eye roll)) This is my local area extension services...we are SW Ga.

While your local extension agent may not know anything about walnuts - there are folks whom they can call upon for information. Former county ag agent here only cared about tobacco production and not much else; current one will help with anything - and if he doesn't know about it firsthand, he'll hunt up the appropriate university 'expert'.

While he's well-known as a pecan expert for his 45+ years of work with them in GA, Dr. Darrell Sparks(or some of his fellow researchers) may also have some recommendations for Carpathians suitable for GA - or they may be able to say, unequivocally - "Don't waste your time with them."

Here's the section on Carpathians from an UGA Extension bulletin on minor nuts/fruits:
Carpathian Walnut
The Carpathian walnut (Juglan regia), also known as Persian or English walnut, is believed to have originated near the Caspian Sea in Iran. The Greeks and Romans brought it to the west, and it was eventually spread throughout the Far East and North America. Carpathian walnuts are sensitive to climate extremes and are marginally adapted to Georgia. They are quite susceptible to spring frost injury. Temperatures below 12 degrees F will kill some varieties, and temperatures above 100 degrees F will cause sunburn on limbs and shrivel kernels.

The walnut is monoecious, but cross-pollination is required; so at least two varieties should be planted.
Carpathian walnuts do best on deep, well-drained soils with a pH of 6.0 to 7.0. A spacing of 25 feet by 25 feet is ideal. Carpathian walnuts are propagated like pecans, but no specific variety recommendations can be made.