In that case, it should be no debate what his next move should be. Unify all 4 titles and get the ring belt.
The answer to your question is yes but the IBF are putting heat on Vic to agree to defend against his mandatory next up. Showtime won't take that fight so Vic would need to do it in Australia in order to keep the IBF belt. I don't think fighting for the WBO belt would give him The Ring belt. Truth be told, he should already have The Ring belt after unifying against Mijares but the ding-a-lings at The Ring have withheld recognition. Donaire will be ranked highly at 115 after he debuts there. Vic will likely need to face and defeat him in order to get The Ring belt. The scenario I envisage going forward is that Vic hangs onto the WBC & WBA belts, takes a non-title tuneup in Australia in September, then back to the US for a significant fight in November. Had Vic beaten Agbeko, you would have seen him in with Rafael Marquez at 122 in November. That was all but a done deal.
His undisputed championship wasn't on the line. But BW fight or not, these criminal organizations would've forced the mandos anyway. Latest news is Vic planning to fight yet ANOTHER, the 5th world champ in a row in Jose Lopez therefore losing the IBF, but who cares, he's undisputed, how many ABC titles he holds is irrelevant.
yeah, this fight with Agbeko has consumed a lot of time to fight his mandatories. I expect him to keep the IBF out of loyalty though and its good standing with Australian boxing. A fight with #2 ranked Munoz on the ring rankings should give him the ring belt without question, but besides that a fight with Munoz just screams out fireworks. I hope it happens soon, hopefully no later than early next year.