there are presentments for both John McDonald + Ellinor Harrison both in Rushen in the same court in 1727 - Eleanor was noted as absent thus it would seem to indicate that the earlier Jony was illeg and possibly the one you seek
There is a will for John but I havn't seen it - catxch is I'm now going to be off Island for a couple of weeks so can't see the wording of the presentment nor find John's will