Mystique:
You have the same mutation that she has and you can suck people's power temporarily. Your mutation suprised her very much. She thought you will have similar powers, but you got the exact same thing with a bonus.
Jean:
You have her telekenisis, but stronger. This way, she really knows you're her child. But it sometimes scares her that your telekenisis has farther limits than hers. If she can destroy a city (or smth look at X-men where Logan kills her), you can destroy a country as big as France.
Charles:
You have control over ice and water. You froze a small pond on a tiny island your father took you once during summer. You still visit there from time to time and the pond never melted. Even if the island is located near the equator.
Eric:
Nature manupilation. When you first discovered you have it, you were scared that your dad will be very disappointed because nature manupilation is very weak compared to his mutation. When he finds out, he told you that he's actually very happy about it. You have power of everything around you since nature is literally everywhere.
Logan:
You can steal someones senses. (Smell, Touch, Taste, Hear, Sight), increasing yours. He is very aware that this power can drive someone nuts. And he knows that you can take anyones-including his.