Yeah, I think that's right.

I plan on using the 1" drains with gate valves.
Using the 3/4 drains as the emergency drains.

Plumbing my returns over the top.

Will adding a "durso" to the drains accomplish anything?

(or just leave the gated main drain as just a straight standpipe?)

Throw the durso standpipe in the garbage IMO

For your to main 1" drains put a standpipe with a strainer about half way up the overflow box, with the 3/4" emergency drains put standpipes going 1/2"-3/4" from the top of the overflow box with open pipe no strainer

Make sure all 4 drains have their own deprecate plumbing down to the sump, if you plumb the emergencies in with the mains it defeats the purpose of the emergency and creates alot of noise