Coming from the southwest I've used mesquite a lot. I can say nix the ec-1118 and go with something less attenuative, D-47 is a really nice one if you can keep the fermentation temps down. Mesquite is also not so good bone dry but i've never aged any that came out dry to see if it improves. I'd say less aggressive yeast, good fermentation temp control, a good oak adjunct (American cubes are good for the Mesquite flavors) and a medium dry (1.006-1.010) to sweet finish is fantastic. I recommend a long and complete fermentation and aging on oak, then stabilize with sorbate/sulfite or sterile filter and bottle, then lay down for 6+ months, though with a medium sweetness it'll be acceptable around 3 if the alc% isn't greater than 14% or so.
I used mesquite honey for a roasted hatch green chile batch I did and it came out superb, the honey aroma lifts out from the glass long after the mead is gone, and the heat is flavorful and reminds me of late august in my city when there's roasted hatch green chile vendors everywhere and the smell permeates the mountain rain-soaked air. Sorry for the tangent, I love mead