I am Dave's second cousin and live in the Isle of Man where I meet Alan and Roy occasionally. You probably have all the information available on the Manx side as Alan and Roy must have read every piece of paper in the Manx records relating to Killips and a significant portion of the UK records too. Nevertheless, who knows what may be unearthed during research.
I have much of the same information exchanged on this forum and am currently researching my father's mothers ancestry (Richmond) that takes me back in Manx records to about 1811 then to Liverpool and eventually (hopefully) to Normandy during the Viking era. I will be spending some time over the next couple of years in Liverpool, Chester and Lancashire searching various sources of records - it is possible I may unearth something to help you.
What exactly is it that you are looking for in relation to Thomas Killip - is it just the date he moved to Liverpool or are there other uncertainties?