My 2 cents
In the interest of reducing the "things to worry about" list by one, we're heading to vinyl. The Manningto Adura country oak rawhide looks fantastic. You can tell its synthetic up very close...perfect seams, just a hint of glossiness (is that a word?).
But overall it accomplishes 95% of the look without much of the heartache of real wood.
From here the questions appear to be 1) is there anything around that price that is better (however you want to define) and 2) what is the best underlayment? (incremental to the above comments)
If it matters -
The first living floor will have several inches of closed foam under the subfloor.
The house will remain sealed virtually all of the time. The wind/heat/humidity don't really lend itself to opening up the house much.
Monarchy:
Take this for what it you're paying for it. I haven't looked at that particular Mannington product. I used to really like Mannington for their stylish products, but I dropped them almost 3 years ago because on a teak floor I sold and installed they wouldn't honor a claim on. I replaced the floor once out of my pocket after it failed less than two weeks after installing, then the second one did the same within two weeks. Won't bore you with the details, but they had changed the product vs. the samples, engineered it to be cheaper construction, and have stonewalled me with total bogus arguments and won't release the inspectors report. All together cost me probably about $32-33K to make it right and an unhappy client I had done over $200k with - put an end to that relationship. So I have nothing good to say about them.
My favorite brand of luxury vinyl products is Karndean. (NAFCO is good and probably a couple of others that maybe others can comment on.) Top end price retail for all except one of their products is under $6/SF for the product. Glue will run about $.10-.20/SF. Cleaning and care kit should last 1-2 years is about $55 retail. The Oak Royale product comes in 4 colors, looks like a hand-scrapped antique oak, and I retail it for $5.49. Installation on these products should be less than hardwood or laminate. Some people are installing for $3.00/SF, which is ridiculous. Depending on what you pick, expect $1.25 to a max of $2.00 for install. (Heck, for $3 I'd be tempted to come do it myself if you had enough footage.) If I remember right, you are getting into building and can probably get a trade discount if you work with a good store. If they support you well send all your professional business that way, too.
The Oak Royale (and one that comes in 3 dark colors that looks like an antique hand-scrapped hickory) are Very Heavy Duty Commercial. But they have something like 9 lines, from residential/light commercial to commercial to heavy duty commercial to very heavy durty commercial. You can also get it in tile looks that will match up height-wise if you want to do a kitchen or bathroom or sunroom in a tile look. Retail on these runs from about $3 to $6 on all but the very most expensive. I don't like the Island Limestone (the most expensive) much because of how they package it and recommend installation. All the rest are fantastic products.
IMO, you would get get an excellent sub-surface from using Adventek T&G for the subfloor and an underlayment like Fiberock, then the lvp. Or, and this has been discussed on antoher thread recently, two layers of subfloor laid at 90% to each other then the Fiberock. If budget is an issue you can use B/C plywood or two layers of OSB, which would be cheapest, or one of each. First layer would have your studded walls on them, second layer would be "inside" the studded walls.
Question is if you use adhesive on the subfloor and nailed or screwed. I believe in screwed. Using adhesive will give you a lot stronger fit or hold, but if it ever has to come up (say from a water line breaking) it is an absolute bear. Some of the other guys here can give you tips on making sure the joists are level, no crowned edges next to a joist that has a concave side up, etc. Use a straight edge to check before doing subfloor and sand anything smooth and level.
For most lvp/lvt products I think you are going to have similar methods. Make sure you don't have ridges or rolls in the subfloor or it will be transmitted up through the vinyl and show every flaw of your subfloor. Good luck, let us know what you select, and I'm sure you will get good advice from some others here.
