This makes good sense to me. I can't see wanting to drag sewer hose under the trailer, or try to get into a one-way dump station the wrong way.
I don't see a need to weld the stabilizers on - I like the idea of being able to replace them, remove them for repair, or maybe move them (don't they drag in some places? - maybe the trailer overhang is so short it's not a problem). There are square-cornered U-bolts, which would be a tidier fit if you can find the right size, but the current setup looks fine to me.
Have you thought about mudflaps or other guards? Maybe I'm just used to the idea of lots of rocks on the road - my Boler
came with a split in the front of the greywater tank from road debris. ABS pipe is tough, but not invincible.