When I visited the Canary Islands, one of my first thoughts was just how formidable a landscape it is, you can well understand how the Gaunche put up such a fight over it. I don't think a quick conquest is possible.
The Marinids (who are the most likely candidates) were highly competent and could have easily conquered had they developed deeper water capabilities.
Is there a reason you think the Marinids are more likely to be the candidate than the earlier, more powerful, Almovarids and Almohads? All three, has the military capabilities and all three were distracted by internal strife and wars in Iberia and didn't really have deep water navies.
Obviously the earlier it was, the more likely the Muslims are to be entrenched. I'd suspect a Marinid conquest would be contested by the Christian Iberians, if not with their own forces at least by arming the Gaunches, given they were already both visiting the Islands and raiding Moroccan cities.