The downhill side needs an overflow assembly, or your sump will flood when the power goes out. I am not sure if there would be a problem on the uphill side. The instructions say that the filter needs to be lower than the tank for normal operation, but ths isn't really normal operation. Also you'll need a check valve on the input end of the uphill side to keep from losing siphon in that direction - and it might be a pain in the posterior to prime that side if you can't backflush to siphon water into the canister. (If yu got a spare quick disconnect, you could have one with the check valve for operation and one without for priming.
So - overflow on the downhill, check valve on the uphill, no guarantee that the uphill side will work, and it'll be a real chore to get running again after cleaning.
You might be better off hooking them up to the tank in the standard fashion, and using an overflow box to the sump and pump back up.