FWIW, the fear of "mixing & matching" is mostly a made up issue that's not entirely true. OME uses the same struts/shocks for their HD and MD springs which have quite a range of spring rates..... They're not exactly "fine tuned" to a specific spring; they're "tuned" to work with a range of vehicle weights (WK 3.7L to XK 5.7L) and spring combos. When they start offering shocks specific to the actual vehicle and spring being installed, then you'll want to be careful.

The 5100s are valved more aggressively than stock and they'll match up fine with either the HD or MD springs.

For the rear I would recommend getting the 5125 series shocks since they can be ordered to the proper length for maximum travel and you can select valving to your liking. Since you like the N190 shocks I'd go with the 255/70 valving on the 5125s.