Bryan...

I found the answer to my own question. Immediately after the second split Holmes group can return to Brahd by choosing to visit the Inn from the main map. And he can also revisit Ligria via an encounter and complete the Ligria forge side quest using a master sword obtained at Brahd using Runan's guild key or the master sword obtained on map 23. However, unless you need additional visits to the secret shop I'm finding the 2nd guild key to be not needed.

My fellow FE fans, To get the guild key in Holmes Route... I see you need to complete the forging side quest. However, I cannot figure out where to get the master sword needed to complete the 3rd forging. I see you can get it from map 23... but is that too late? The only other place I see it is from the mermel caves encounter but that is a 2% random chance to get it from a chest which would be miserable to farm. So if anyone has any knowledge about this I would appreciate your feedback. Thanks,