Given the gap behind the tank, you may want to consider a one piece toilet. They are very strong and you don't have the tank "floating" on the back of the bowl. I think that Toto offers a 13" trap assembly that can bring the tank back to the wall. We have a Drake and my wife hates it. It flushes very well but there are ridges, one at the water line and up under the bowl rim. As well it has the exposed trap on the side which is a pain to clean. Sometime in the near future I am going to buy a skirted one piece. It will be a Toto, I'd suggest you make a point of demonstrating how toilets are cleaned to the boys and add it to their chore list. You are The Mom and while you will do everything for them, in this case I think you should " pin the tail on the donkey."

what about the cadet 3's quality was questionable? from everything i've read here on the forums it seems to be a highly rated, reasonable priced product. run a search. there have been many discussions related to this particular unit.

Just one other quick note-- you said something about adding cement board and subway tiles to the drywall. First, you can go right over the drywall with the subway tiles if you wish in all areas except where there's a showerhead. Secondly, if you DO decide to use cement borad, there's no need for the drywall. Just use 1/2" cement board in its place.

No offset or reducing flanges: International Residential Code IRC-3002.3.1 & UPC-408.5 These rules have been in the codes since the late 70's or early 80's. The question then becomes, why do they sell them? They are legal for maintenance but not for new work so the question then becomes, what is maintenance and what is new work? It is assumed by code that a system must pass a complete code inspection at the time of initial installation. By code definition "maintenance" is the act of maintaining a system in its existing configuration. Any change or alteration to the design or layout of a system, no matter how slight, constitutes new work, and ALL new work must conform to the code that is in force at the time the work is performed. Therefore, if they used an offset flange when the building was initially built and inspected we would be required to install an offset flange to maintain the system intact. If we desire to move a fixture, no matter how slight the distance may be, that is technically defined as new work and the use of an offset flange would then be expressly prohibited.