What exactly do you mean by Christian European state? Do you include areas that were not independent states at the time? You have some European states today that have a majority of Muslims, like Albania and Bosnia and Herzegovina, but they where not independent states when they became majority. You need to specify the question: How large percentage of the population must become Muslims in order to count as "turning Islamic" and must they be inedependent states when they became Islamic? Islamic areas were in the past often ruled by large empires, not smaller kingdoms like what has been usual in Christian European countries. And of course, if you include areas that were not independent at the time, they would not necessarily become independent in the same form they did if they became majority Muslim. Maybe they would not even become independent at all, but prefer to remain part of a larger empire. There may be a lot of butterflies in this scenario, and the Ottoman Empire might perhaps not disintegrate to the same extent that it did OTL.
If you include areas that were not independent at the time: Were Chechnya at any point a Christian dominated area? If so, make Russia disintegrate to the point where Chechnya becomes independent.
About the other question? Maybe Morocco if Spain continue the reconquest to the other side of the strait of Gibraltar and follows the same policy of expelling those who refuse to convert to Christianity? This one is harder and less likely than the first one, though.