On the first paragraph - That's not what it means, it would be allowed.
On the second - As others have said, if we had a serious injury to Cam, BdK or Vaulks over the next few weeks, we could bring in cover at the expense of losing Romeny between whenever he's fit and January (likely only a few games based on earlier reports)
I wish people would stop posting about free agents as though they're cheap, they're not. Decent players who are free agents are in a stronger position to negotiate signing on fees or increased wages. The cost of buying players is about Total Cost of Ownership over the contract, how that is made up is largely immaterial.
I get you don't like them, but suggesting they're not good enough for L1 just makes you look soft in the head.
It would likely be Campbell, who's been training with the squad during pre season so would likely be squad ready (don't forget he'd be signed to sit on the bench if ONE of our starting CDM got injured)
All loan players have to be included in the squad list, so it's not the same situation. (Most) People aren't suggesting Romeny should have been left off entirely, they're suggesting leaving him off temporarily in case we needed that spot in an emergency, that was never an option with Nelson, it was include him or cancel the loan (if cancelling the loan was even an option, that's a contractual thing we don't have access to)
My own take on it (the squad list) is that registering Romeny probably suggests that his recovery is ahead of schedule, or alternatively that GR believes one of the other signings could play further back if required in a bind. From what I've read, that may be Krastev, but I've never seen him play and only going on comments from foreign journos about style of play.