That's right all the real info is there. Laying out the top piece by these measurements will give you all the angle and lengths of the parts required for sides and braces and the dimensions on the plenum provide all you need for that. The biggest reason I am not in a hurry to make a set of drawings is that they are not really needed to build by. What is missing is the 19.5" tall motorboard which I will post later today. This is pretty simple to build other than the size.
Claude has made recommendations and he is the numbers guy in this. While this is my idea he is the one who tells me right or wrong. You will have to ask him about this and I would say for sure using 12" is a no no without any doubt. If you are considering building this and putting the time and money into it I would at the very least use something designed for it. K-43, K-33 or Crites woofers are all I would consider at this time. There may be a better one out there but I am not looking.
I have a very similar room layout including all the toys
My layout mirrors option 2 but I'm using a set of RP-150Ms as the surrounds instead of dipoles. I try to hog the sweet spot most of the time but others concerns are right, people sitting close to those speakers get a very uneven experience. If you have Audessy, MCACC, or equivalent make sure you run it to balance it out.
Also, You may want to add a rug and some curtains to diffuse some of the sound.
Heck. I think with all the info in the pics I can build one I have some 15” and some 12” drivers I could use. These are for a 15” ? What t/s numbers should I look for in a driver for this box ? Great work as always