The first phase is the top left two blocks here - http://royalcanalpark.com/site-plan/ with the top one ready to move in end of Jan (middle of Feb) and the one below ready to move in mid March (late April).
The next phase is to be released in January, but obviously that'll be at least February.
It's not completely clear how large that phase will be, whether it's just the Royal Canal Avenue/Phelan Park block or whether there'll be more to it.
After that they said July I think, which is probably September. That may complete the site or there may be another phase after that. There were 29 houses in the first two blocks so I'd say the odds are good.
Even if they're all gone from the Royal Canal Park end, take a look at planning application 3666/15 on http://www.dublincity.ie/swiftlg/apa...iteria.display
It's up the Rathborne end but also lots of houses and apartments. It hasn't got final approval yet, but it will do eventually and the house types are very similar.
There's also a third site between Royal Canal Park/Cassian Court & Rathborne Avenue/Ashtown which will almost certainly be developed at some stage, but has no new planning application as yet. (It's where the school is planned to go too).
In short, there will be options into the future, though if being close to the Luas is among your priorities, get in sooner rather than later.
The total planned population for the area is just over 6k, current pop (2011 census) 3.2k.