Sources at the network tell us the main focus for honchos is still completing a full investigation into whether or not T.J. and Amy's relationship violated company protocols. They're also looking into additional reports of affairs Holmes might have had while employed at 'GMA' -- including one with an intern -- and any potential issues there.

While some reports have speculated DeMarco Morgan -- who has been at the 'GMA 3' desk during T.J. and Amy's leave -- has already been tapped to fill Holmes' spot permanently, our network sources say that just isn't the case, and he isn't currently being "tested" to take over the position.

The same is true for Rhiannon Ally, Gio Benitez and Stephanie Ramos -- who have all covered the show's anchor desk in Amy and T.J.'s absence.

We're told if and when ABC looks to fill spots, it'll be after the investigation has totally wrapped and Amy and T.J.'s fates are decided.

TMZ broke the story ... both T.J. and Amy have lawyered up in recent weeks -- Amy with Andrew Brettler and Holmes with Eric George -- to possibly take legal action against ABC.

We're told if the anchors are shown the door, their attorneys are ready to file suit, and raise the issue of race -- asking the network, "Has ABC ever used the morals or conduct clause to fire or discipline 2 consenting adults at equal levels when both were white?"

Of course, we've seen T.J. and Amy out and about living their lives as a couple since getting pulled off the air ... spending the holidays together and even hanging out the day before he filed to divorce his estranged wife.