The dominoes will hold the boards in alignment, but the mitres will not be glued together from day one I imagine. End grain doesn't glue well. I would add a few more dominoes if you can- these are your best bet for keeping the mitre closed.
After the glue has tried, if you have any gaps in your mitres, check out William Ng's video on youtube about fixing mitres. It is really easy and very effective.
Glue like PU construct glues end grain very well. But saying that I have not tried PU construct on maple... So don't know
Yellow glue is always very poor on end grain.