Will an immersion option be available for Irish in the future?
As Knocksedan already mentioned, Duolingo is no longer focusing on Immersion as a source of revenue and will not add it to more courses (including Irish), and there have even been A/B tests to remove it completely.
However, there is an unofficial way to access Immersion for Irish (see here). It's not exactly what I recommend, but it is at least there if you want to try it out for practice.
No. Duolingo stopped developing the Immersion feature a long time ago, before the Irish course was added. It's no longer considered a core feature of Duolingo.
Thanks to all for replies. I had been feeling a bit guilty about not participating on a regular basis in Spanish and Portuguese immersion, but I'll direct my energies in other directions now. I appreciate the links to find Irish to read.