There's a similar thread for Fair City, so I'll start this one for Ros Na Run, and I'll start things off with:
Dara does the maths and realises he's not the father of Caitriona's baby.
Grace/Alice to become desperate and do something horrible. I'm pretty sure she's already poisoned Bríd. I bet it'll backfire and Vince will end up sick.
I also think Tina will be first to twig that Dara is not the father of Catriona's baby.
Grace to end up pregnant, or tell Vince she is anyway.
Jason comes clean about the murder
Tina gets off due to lack of evidence and Jason gets away with it.
there is something wrong with Tina's baby and he/she needs something like a kidney/blood donation preferably from a sibling, caitriona obviously says no,
so dara sneaks the dna sample behind her back (to at least see if maeve is a match) while also getting tested himself and finds out the truth he's not Maeve's dad.
Marie and Peader decide not to return to the village (probably obvious now by the for sale sign outside their house)
Brid admits to stealing Micheal's lottery ticket