OP: Stay with your 24 - 27' plan as it will suit your projected use much better. An island queen in a C under 32' is the most overrated feature I have ever seen. If you are like most folks you will spend 8 hours asleep and about 30 seconds getting in and out. Hardly worth all that you have to give up to get that walk around queen {keep in mind that in most the term "walk around" is relative}.
For you and your boys, the rear corner queen and the cabover will work well and you still have the dinette option. Have yet to see a jackknife sofa that was actually anywhere near comfortable to sleep on. Our horseshoe-shaped dinette is very comfortable and actually makes into a real bed on those rare occasions we need it. Most folks who actually camp spend 10 to 13 hours a day outside so the interior layout matters little except in inclement weather. It all comes down to how and where you will use the rig.
As always... Opinions and YMMV.
:C