You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new. I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood. It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above. You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to. Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there. I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that. BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion. And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

3/8 solid and 3/4 solid, are going to be a long term, resandable surface. The 3/4 can be refinished and sanded down to bare wood, more times then a 3/8. That is the only trade off. 3/8 helps and is much easier on transitions to other flooring. Engineered vs. solid has been hashed out many times over. If your going over a concrete foundation, or have concerns with dramatic humidity swings, engineered is the flooring you need.

Choosing the right flooring type isn't enough for your living condition. You will have to consider the types of cut: flat sawn, rift and quarter sawn, quarter sawn or live sawn. Quarter sawn and rift & quarter sawn will be best choices, because expansion and contraction is along the thickness of the wood. You will need climate control all year round. 70 degrees at 40 % relative humidity is where you want to be throughout the year. The use of a humidifier/dehumidifier will be needed year round. Although, engineered flooring is more stable than solid. Using the wrong wood specie in your living condition can run the risk of de-laminating with engineered wood. If, the top veneer is more or less stable than it's core and backing. You will experience de-laminating in extreme humidity swings. Take in account of what the engineered flooring is constructed of: mdf or plywood. The width of the flooring will account for how much expansion and contracting also. 2 1/4" strips are the most stable. As you go wider, expect to see more wider seasonal gaps. Proper acclimating is critical, should be performed with a moisture meter. For 2 1/4" strip flooring , sub-floor and flooring moisture should be within 4%. For all other widths 2% moisture differentiation is allowed or should not be exceeded. Don't forget proper expansion gaps, which is the thickness of your flooring, example: 3/4" thick = 3/4" gap. Sub-floor type and condition will affect the performance of wood floors. All this needs to be considered for the proper and successful performance of your wood floors.

Leather is the most 'recognizable' pattern for cork (other than the ground up cork board look). When it is laid it looks like hardwood flooring using 'shorts'. It has a bit of a brick look to it. Ignore the 'pink' in the samples. The pink is the very first colour to fade away. It takes a few months for the pink to disappear but once it is gone the cork (Leather and Logan) will look more like oak in tone (yellowish with some hints of green and some gray). It is a 'directional pattern' which means it has a 'linear' sense to it. The Logan is the most expensive cork pattern you can get. The slices of pattern are random. They are hand cut and hand laid. It takes *roughly an hour for 1 person to arrange 10sf of the pattern. It is STUNNING. It looks more like stone. It is random...did I mention the pattern is random? Leather and Logan can have the extra 2 coats of the Loba 2K Supra AT = super tough. The Latte is a FANTASTICLY tough finish. It has the polypropylene finish on it. This is the 'non-vinyl' product Cancork sells. It is tough....right after that it is SUPER TOUGH. And then for good measure, it is TOUGH!!! For a Rental property, the Latte is a product I would recommend. It does NOT need the Loba product. That means you save $1.50/sf RIGHT AWAY. It can handle 3mm or 6mm cork underlay. If you are looking for temperature control, then I like the 6mm underneath...but CHECK your door heights, etc. All you need to do is take your floor sample and the underlay sample they sent you (their supposed to do that...sigh) and see if it 'slips' underneath the doors in your home. It is that simple. I hope that helps... As for the Tacoma...I'm guessing you are looking at KILOGRAMS (700 kg) as your weight limit = 1540 lbs. The weight of a standard skid of cork flooring = 1000sf (ish...depends on the product) = *roughly 2000 lbs. And the skid sizes are PERFECT to fit between the wheel wells of a truck bed. I've watched this stuff get loaded into pick-up trucks for 6+ years. A forklift operator can drop that baby into your truck (so long as you do NOT have a 'cap-it') and off you go. If you only have a short way to go, the 2000 lbs won't be much of a problem...I just wouldn't do a trip to Bella Coola with it. ;-)