Sooo adorable! They are all so much fun to follow on instagram! Actually they are the reason I signed up for an instagram account in the first place, so I could follow them.
How's twitter for Celtic Woman stuff? I don't have an account, but maybe I should if they are active on there.
Usually there's quite a bit of overlap between Facebook, Instagram, and Twitter. While some of the girls only use one or two of those platforms, most of the active ones on social media use all three and many of them post similar content on all 3 platforms. I too started using Instagram and Twitter because of Celtic Woman. Personally, I prefer Twitter for interacting with Celtic Woman. For me, Facebook is becoming too cluttered to follow things from a Celtic Woman 'news' standpoint, although it's the best place I know of to interact with other fans.
Mairead Carlin and Tara have been pretty active on Twitter, as is the main Celtic Woman account. Lisa Kelly does Twitter from time to time. Chloë does quite a bit on Twitter, although she's pretty selective about liking and responding to things.