My older-style Matrix blades did not fit the holes of my MK Dance blades (both 9-3/4"). I was told that even MK blades, from one model to the next, aren't always a perfect fit, but haven't confirmed that. I think I may have gotten away with using the same holes for MK Dance and JW Coronation Ace, but am not certain any more, and I may not have worried about getting an exact countersink mesh. But there are enough differences between my blades and yours that my experience on that may not apply.
I wonder if someone here plans to visit a skate shop that would have your size blades for both types of blade that they could look at.
If I remember correctly, an Edea tech who probably trained other Edea techs (he was the North American distributor) mounted blades to Edea skates by drilling all the way through (after removing the insole), and screwing bolts from the outside with something like a very thin roller skating nut on the inside, and putting the insoles back in. You can do that with ice skate blades too - I was told that some high level skaters did it so they could swap blades more quickly. E.g., between freestyle and dance blades, or so they could ship their blades for sharpening to their favorite skate tech. It also makes for a more solid connection - you can easily strip a screw hole in relatively soft sole materials by overtightening them, though I'm not sure if that is true of Edea sole materials. In contrast, metal bolts and nuts don't strip as easily, if you are careful.
But that is not the way most pro shop skate techs have been taught to mount blades, by screwing self-taping wood-screws into leather soles.
Also - while to some extent you can sometimes get away with not plugging holes in normal mounts - though in leather that can sometimes lead to rot. (Do the materials in Edea soles rot? I don't know.) But if the holes were indeed drilled all the way through, and the holes aren't plugged, your feet may get wet. I'm not sure, but your feet might also get cold if they aren't filled.
I have filled holes in leather soles with Shoe Goo. That worked with the little bit of overlap I had. But Shoe Goo takes 72 hours to fully set (especially if the holes overlap, so you need the filler to be strong). That's a long time not to skate.
One skate tech (Don Giese) told me that you can accelerate how fast Shoe Goo sets by using heat, but didn't give me any details. Also, from what I understand, you need to be very careful about heat and Edea composite boots. I have no idea how hot you can safely get them. I'd be too cautious to try. Skate boots are too expensive to mess up, unless you have an older pair that is no good to experiment on.
I also do not know if Shoe Goo will bond to the materials in Edea soles. Perhaps you should try a short test inside one hole first?
Another skate tech (Mike Cunningham) carefully shaved wooden dowel rods to slightly larger than the holes, then hammered them in - at least in leather soles. It made for very solid fills, that handled overlapping holes very well. I think that is pretty safe, and its also cheap, but admit I don't know how well the coefficients of thermal expansion for wood match those for Edea soles, and maybe someone with an engineering background could suggest other concerns - perhaps some types of wood would do a better job than others. (I basically tried it for one hole, using a cheap pine dowel. Mike, who had decades of practice and a power sanding tool, did it very fast, but I took much longer using a handheld file. Maybe you could use a sharp knife too instead.) If the holes are drilled all the way through the soles, I guess you should take out the insole and measure the depth of the hole, and cut the dowel to that length first, so nothing pokes into and rips the insole.
I'm sorry I can't give you any details specific to Edea boots. If they were mine, I would try the shaved dowel approach.
Regardless, assuming that the matrix blades have countersunk holes for the screws, be very sure to use countersink screws or nuts on the circular holes. That makes for a tighter fit, and also firmly locks the blade into position. At least in the past, Matrix blades had the countersink properly centered on the hole in the blade, but MK blades didn't always do that quite right. So you may want to use a "countersink punch" to center your pre-drilled pilot hole on the countersink, rather than on the rest of the hole in the blade. (Mike could do it by eye, but I'm less coordinated, and can't do it well that way.) If you have access to one (they start at about $20), a "drill guide" will also help you drill the pilot hole perpendicular to the top of the blade, so the countersink will engage fully without warp. I also suggest you try to avoid warping your blade, by first using tape (I like cloth first aid tape, which maintains its shape well over time) so that the top of the blade plate exactly fits against the shape of the bottom of the boot, without needing pressure to warp it. Experiment with how many layers you need in each position on the boot to get that perfect fit. I think Bill has described using Silicone sealant instead - I'm not sure how you do that under pressure without warping the blade.
Since the sole is synthetic, I think, it is possible you don't need to waterproof the bottom - is that right, guys??