I am still not a rebreather diver, so take with a grain of salt
It looks like having the BOV out front or under the DSV could be annoying..
How about.. inserting a valve in the inhale hose between the DSV and the counterlung.. close to the counter lung.. then on the DSV side of this, install the ADV... then on the exhale side, put a OPV and another valve..
On problem with loop, close inhale side, now when you inhale it triggers the ADV, on exhale you start filling up the exhale CL... Then you can either let it continue filling till it starts triggering the OPV on its own, which would obviously increase your buoyancy... or close the valve between the OPV and the CL creating a bailout through the normal breathing loop without sticking a regulator farther out on or below the DSV..
In a little bit I will scribble something out in illustrator
-Scott