Yeah i dont think that will happen. Look at his talk with Amy and Ciarara in his mind.
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To me it looks like neither of them took Noels' spot, its still empty and like its reserved for Noel only. Its Noels' chair since they bonded and it stays like that till shes back imo no matter what happens with or to other bonds.
Therefore at the moment i guess its safe to assume that the mc is able to bond with (at least) three dark ones at the same time and maybe more.
I kinda depends on if it was the mc himself via his "rulebreaker-powers" who reserved this spot for Noel or if Nael made nessecary arrangements for the MC and Noel to be able to bond again no matter what (as she promised).
And i dont think Nael will ever bond again if Gab dies (she doesnt need to and only did it because of love and shes gonna be broken afterwards) but she may supports us via a tear or something like that again.