... In Alicia's death there isn't a 29 Feb 1869, and can't find her death registration so possibly not registered at all.
... There is no death for Alicia on the Irish Genealogy website, which is where I had been looking.
Nearly all deaths from 1864 to 1870 have yet to be digitised, they paused a long time ago when they got back to 1871 with the promise of picking it up again in due course, but never did pick it up again, presumably due to lack of resources.
The births in that time period were indexed but had no images, but they appear to be there now.
Images for the birth records on IrishGenealogy have been there since at least 2019.