The short answer is yes.
The expensive answer is I think I saw a big pedalboard that has enough stereo routing and outputs to send the usual front end effects in the front of the amp while sending the modulation effects through the effects loop. I would expect this to become standard on the high end equipment if it isn't already.
The hack answer is if you can send a stereo signal to two amp front inputs, you can just run the same cables into the fx loop return for each amp.
However, the Fx loop will probably be AFTER the amps preamp section and what you will get is whatever preamp the Fx loop has going into each amps power section.
I use this to skip the guitar preamp on purpose myself.
But not for tube guitar sound.
Usually, the preamp section of an amp has a lot to do with the "character" of a tube amp.
Digital preamps can be uncolored preamps like the Fx loop preamp(if any), or intentionally colored like a tube preamp.
But there's another issue concerning "stereo" delays in particular...and your intended use of having one amp for distortion and one for clean.
A delay takes the signal, splits it, then delays ONE SIDE of the signal.
If you split the delayed signal to the distortion, and the undelayed signal to the clean, there might be a strange increase or decrease in volume coming from one side. It could sound bad or cool, depending.
As you appear to be suggesting you are going to try and run a distorted AND clean amp together for a sort of layered sound, with the delays etc in stereo, you'll have to decide if you want the delayed or undelayed sound to come from the clean or distorted amp.
But as I said above, running stereo outputs into the FX loops of two amps might turn them both into CLEAN amps if the volume isn't loud enough to push the amp section of the intended "distortion" amp into distortion.
That, of course, would make one amp really, really loud.
Now in my stereo rigs, if fed by mono fx, I simply use a stereo pedal or ABY switch to run the fx I want going in the front of two amps in clean mode.
Then I have stereo delays etc. for the fx loop.
Run the fx send output from each amp to the stereo ins on the delays, and the stereo outs back to the amps fx returns.
If you have two mono delays I suppose you could have a delay for each amp. This has it's use as well.
And could be fun !
And that's the point of this.
The way I define "stereo" is when both sides are the same equipment, with the music eq/channels moving from side to side.
The way your described equipment is set up, both sides are eq and possibly volume different.
And that's pretty fun !
You'll just have to explore and see what you like.
