I'm currently shopping loopers and prefer the "buy once, cry once" mentality but also don't want to overbuy only to find out my current simplistic setup cannot take advantage of a pedal with too many features.

I'm looking at the Boss RC5 and RC10R, and my intention is to plug the pedal into my DSL40's effects loop rather than in-line with the guitar input.  My understanding is that in this location, the looper will receive the clean/overdrive/distortion tone I use when recording the loop, and play back that exact tone through the power amp, and the drum functionality in these pedals will be uncolored by the DSL40's preamp.  Is this a correct understanding?  I should be  able to record a loop using my clean tone and play back a clean tone after shifting the DSL40 to overdrive channel to accompany the clean loop with an overdriven lead, right?

Where does the DSL40's onboard reverb come into play in the effects loop?  Before or after the effect loop return?  If the loop pedal I buy has onboard reverb it can apply to drum accompaniments, will the Marshall reverb also be applied to it when it comes through the amp's effect loop return?

And finally, while this isn't a 100% Marshall question... how would one go about playing into a pedal like the RC10R and looping one's tone created on a DSL40, and then when time to play back the loop content, have that output go to a more neutral amplifier while still having guitar played through the Marshall?  I can't think of a way to do that short of micing the DSL40 and pushing that input into the RC10R, then having the RC10R output to a neutral amp.  If I send the effects loop out to the looper, will the DSL40 still play if there is no return from the looper?  Can i use the effects loop send like a signal splitter at the preamp?