Converting a 24 Semcycle XL to a 26er

I am thinking about converting my Semcycle XL into a 26er. It’s been a while since I’ve built a wheel and thought it’d be fun to make it into a faster road uni.

Q 1. The frame looks like it will take a 26" wheel, does anyone know for sure?

Q 2. With the changing of the wheel sizes for racing, will the 24 still be used for some of the events? I hope to make it to a competition this year and need to know if I should build a complete 26 wheel and keep the 24 wheel, or should I tear apart the 24 to use the hub and cranks for the 26?

Q 3. If using a tire of approximately the same width, how much difference for riding (speed and other riding characteristics) does it make to switch over to a 26 from a 24? I know I could do some math and figure it out, but I know some of you have done the math already.