You can reuse ARP studs. They are of a grade where the tensioned value of the studs brings them into a state of ~65% of the yield point. It might be a little higher than that.
The roll dies that ARP use are good, but one of the attributes of the special ARP Lube is that in comparison to other types of lubricants, the threads don't polish out; the scatter is lower between how often you retighten them. That, however, depends on the product and is shown within ARP's own data.
Using the 6.0L stud.
The one Detroit #2 ("Peanut Butter") data point is an outlier and probably bad data. Detroit #2 has good lubricity but is known to allow polishing, so the same amount of 210ft-lbs of torque would take the ARP stud to yield and failure with multiple "polishes".
Thread polishing still occurs with motor oil (10w30) and Moly D reinforced lubricant. APR lube is a very unique product and gets you to a consistent point of Preload, where you would need 6 to 7 re-torques to get to the same point with other lubricants. There are instances with critical fastening where engineers state a fastener to go through that many re-torques to settle out.
MLS gaskets need a smoother surface finish and, as Racer pointed out, clean. I, personally, am opposed to the Ford procedure of not milling and leaving staining.
Engineering textbook: