Hi Jean:
The 5 June 1687 baptism of Patrick Killip in Ballaugh is a very good fit for the Patrick Killip who ultimately married Isabel Quay in the 1710-12 range probably in Lonan. As you say, the IGI has 3 children of Patrick Killip & Christian LOANEY (or LOONEY) who married 9 May 1680. There is a will for Christian Killip alias Loony in 1690 listed on Brian Lawson's site, but it hasn't been recorded there yet. The IGI has one child of Patrick & Mally named Isabel baptized 25 May 1695, so perhaps he remarried.

The baptism 27 Mar 1648 for Patrick, son of John Killip in Ballaugh, is a good fit too. There are wills which will need to be checked out because they could provide clues for us.

Eric.