Re: Question?
Guillaume Dery
Answers in order.
Top held in place by gravity and massive Mortise and Tenon on the legs. This is reinforced by a lag screw through an elongated hole in the rail just to keep it flat and keep from lifting the top off when attempting to move it. The brand doesn't really matter. I think mine are Spax but I could be wrong.
Plans? There are plans? All kidding aside, you can feel free to be fairly liberal on interpretation, you just have to think things through a bit so your joinery doesn't interfere with your hardware. At the end of the day, it's really 2 square assemblies, connected by 2 stretchers with heavy rectangular slabs sitting on top. Many ways to skin that cat. Do pay close attention and cut out all your joinery and fit leg vise hardware before assembling the leg and base. Much easier to bore holes at the drill press than as an afterthought.
hard maple seems spendy for any part of the base, I'd use that for the top if I were you. You aren't really going to be abusing your legs that much.
Not much tooling required, a couple of planes, some handsaws, brace and auger bit (although I did end up snapping a nice Jennings auger bit when doing the holes for the holdfast 
)
Now hand tool purists can block their ears but a router with a half-inch spiral bit lets you hog out a lot of waste in short order and speed up your build considerably as there are a fair number of very big holes to cut.
But a jointer-planer does make life a lot nicer. That being said, I originally had visions of running my top slabs through the planer but was quickly disabused of this notion when I tried to lift and maneuver one. I did it by hand, anything else was an accident waiting to happen. It's actually fairly easy.
So on the power tool side, I would say:
Jointer-Planer is a must unless you are a masochist
Tablesaw definitely not needed. You would be better off with a tracksaw for the same amount of money and you can use a jointer-planer to square things up and bring them to final dimensions due to the large size of members
Bandsaw on the nice-to-have list for quickly cutting out tenon cheeks but mostly for resawing your 8/4 lumber and minimizing waste. Joints can be cut by hand easily and fairly quickly as they are all straightforward M&T.
A drill press is darn near a must so you can keep critical holes at exactly 90 degrees and there are some large ones to bore (bigger than my collection of auger bits can accommodate)
Chopsaw would be on the very-nice-to-have list as most members will be too large and/or heavy to do on the tablesaw (if you aren't going the hand tool route)
Cordless drill, not needed, get by with a brace and auger. Plus some of the torque needed will quickly cook your batteries
mid-size plunge router with 1/2 spiral bit, very nice to have but not a must.
Hand tool-wise
Handsaws, rip and cross-cut, full-size - unless you power tool it, then again you still need the cross-cut one to final cut your slabs as they will be too big for your chopsaw by a fair margin (unless you have a monster tool and budget)
backsaws, rip and crosscut: carcase or tenon saws to cut out all your tenons. Trust me you won't be needing or breaking out anything finer at this scale of work. Your dovetail saw and dainty joinery saws can just collect dust for the duration of your build.
Bowsaw or something to cut curves You could always shape your deadman and chop to not have curves and negate that need. It was much more pleasant using a bowsaw. Mind you it was slow going with mine as my Grammercy blade was too fine and I was too lazy to go get a coarser blade. In hindsight, I would have spent less time cutting those out if I had just driven to Lee Valley and purchased a coarser blade than powering through.
Chisels, all you need are stout bench chisels for this. You won't even need to break out the mortice chisels as the mortices are too large. Paring chisel and a chisel to deal with cleanup of corners are on the nice-to-have list. I did break out my Japanese chisel to clean up the dovetail to avoid bruising but that's not even needed as long as you don't have huge lands on your chisels. My old Marples Blue Chip from the hardware store are butt-ugly but still some of my favorite user chisels.
Bench Planes:
Jointer plane- kind of a must if you are flattening. Longer reference stops you from making dips and hollows.
Jack plane - definitely on the must side due to size. Forego smoother and just use a jack. If you can swing 2 irons on it, one with a large radius for scrubbing and one with a minor camber for final dimensioning and smoothing, that's nice.
low-angle block plane. I love that sucker, great for end-grain like the dogs, doing quick chamfers, easing edges, etc.
Specialty planes:
Router plane. REally a must for cleaning out the bottom of some of your major excavations. Dirt cheap on the used/fleabay market.
Shoulder plane. Unless you are one of the gods of this forum who get perfect joints off the saw.... VERY nice to have. I used mine constantly to tune all my tenons after dry fit and cursing. I have the LV medium one and wish I had the large
Rebate plane. Nice to have. I used mine to shiplap my shelf boards among other things but there are other ways to do this, either power or hand tool.
I assume you have all the marking and measuring so I won't go into that but I will say that having multiple marking gages is a very nice bonus and expedient to layout your joints repeatedly and consistently. I am partial to wheel gauges but that's because they are idiot-proof and this idiot often has a problem with pin gauges following the grain. I am also fond of dividers for marking and layout, finding center, et. As opposed to a compass, I find my dividers cut nice arcs that can be followed or the intersection of which can be used to register against.
Definitely get a cabinet makers rasp. Good for shaping, refining curves, and fine-tuning joints.
The needed toolkit is quite minimal when you come right down to it. Guess what I am saying is don't let the tools you don't have stop you from getting a start on it. Of course, take this with a grain of salt as it's coming from the guy who sat on the project for a few years. When I buckled down it was a few months of work, stealing an hour here and there on evenings and weekends when I could sneak away from the 3 kids and the wife or after they were all in bed (another argument in favor of the hand tool method)
Cheers,
Guillaume
PS: Get on the wood for the top stat. The longer it sits in your shop, the less it will move when you get around to it
PPS: I forgot a crapload of clamps for gluing up the top and other parts 
PPPS: Don't know about the lie-nielsen one but a general rule is that planning for your leg-vise as you put your top together can be a real headache-saver or mandatory (which it definitely is for the Benchrafted wagon vise and the dogstrip if you are doing square dogs).
