What I find particularly interesting is that ine and mac are often used in conjunction with the (accepted) Manx form of the Mac**** heriditary surname, probably indicating that both situations exist during this period, i.e. the change to C, K or Q in the heriditary surname, but the continuation in language of the reference to parent or clan. For example there are instances in the early manorial rolls of different forms of my ancestral surname together: mac Killip, ine Killip, MacKillip and Killip - presumably the earlier forms of mac /ine Phillip had been replaced by this time.

If 1500-1570 is the period of change, and if there was a law, edict or whatever it is likely to be around the time you identify in Peel/German. Perhaps something may be found in the Stanley papers.