Don't do it or go all the way. By all the way I mean lift, 33-35" tires and a regear to suit.
IMO about the only thing 31s on a 6" lift Ranger is good for, is a laugh. Even if you go wide 31s, they look comically small with the lift, and it gains you nothing.
The lift part of normal 6" lift on these gains no ground clearance. You may get some additional uptravel, but from what I can see that is not an issue for you now. What the 6" lift does is give you clearance for running larger tires, in the 33-35" range, it's the larger tires that give you additional ground clearance. If you install the larger tires, you will want to regear to make up for the lost performance.
Your truck already looks good at stock stance. From what I can tell of your past posts it is plenty capable of any conditions you may encounter. If you need a little more clearance in the front, you can gain it by cranking a little on the torsion bar adjusters. You can gain an inch or two just from that to level it out if desired. At one point my truck was running 32s with no more than a level through the adjusters, and never had an issue with tire clearance.
As
@ericbphoto said, do what makes you happy. If that's a lifted truck, then lift it. If you do, I highly recommend going all the way with it.