Her paying rent and taxes doesn’t give her any brownie points with US immigration.
So my question is will she get in?
Her chances are slim to none although not zero. People get admitted mistakenly. If found out on a subsequent interaction with immigration the hammer will come down, hard.
If she doesn’t is there implications for my husband?
She’s an adult so minuscule to no implications for him - unless he somehow gets drawn in during the questioning and tells a material lie to US Immigration which is found out. In which case he will be banned, for life.
Could this stop him traveling to US in future?
See response to previous question.
Also, as there are immigration checks at Dublin, is this where she
would be denied entry or would she get to US and be denied?
Whether it unfolds at preclearance in Dublin or in the USA does not change anything. The same conditions and penalties remain.
Looking for advice
Don’t do it. However, I don’t know her life circumstance that compels her to attempt this in this time of increased immigration scrutiny. Sometimes a human being is compelled to break the law. Over here, we judge no man.
My advice to her would have been to purchase the ticket at the last minute at the airport (or refundable ticket) in which case when she is denied as I expect she will, she can get a refund of the airfare under the 24 hour free cancellation policy.
Finally she absolutely should not lie to immigration if caught out and questioned about her overstay. That way she only incurs the ten year ban for overstay, instead of a permanent ban for misrepresentation. Ten years seems far off, but at least the window to return remains open.