well you read all the pertinent information that is in the rulebook, so no need to paste rules.

the only rule I see is that if something is deep striking you need to let your opponent know when it enters reserves.

I looked up Outflank and it said that you roll when you enter from reserves, but not from ongoing reserves. Not sure if that means you cant outflank from ongoing reserves, or you don't have to roll.

If you were playing and I was TO I would say this based upon what I read.

If a unit enters ongoing reserves then it has two options. 1 is to walk in from the table edge. 2 is to deploy via deep strike, if it has the deep strike rule. If you plan to use the deep strike rule, then make sure and notify your opponent when it enters reserves.