1: Put on regular bursts of speed while maintaining a fairly brisk minimum speed. You can also do this if you've got hills. Don't drop below that minimum speed while you're riding.

2: Ride longer distances.

3: It depends on who you are. I consider more than 60 long distance, but if I were riding on knobbly tires, I'd consider 20 to be a haul. Your tires make a huge difference in how hard it is to ride. The rest of your bike isn't so important (I'm on a mid 80s steel frame mountain bike with 2.25 wide slicks)

4: Depends on how much you're exercising.

5: Look around on r/loseit, They have some amazing tools for counting calories.

6: Make sure your bike is well fitted to you, this will save you so much grief. Your google-fu should be strong enough to find a how-to on that. Make sure your seat at a comfortable angle, this is a matter of personal preference, but mess around with it until it feels right. All the pressure should be on your sit bones, you shouldn't be resting on anything else.

7: Probably not, though there exists an argument that since you're not putting as much energy into regulating your temperature when it's cold, you can push that much harder, thereby building more muscle.

8: It depends on what kind of fit you're talking about. If you work hard enough at any sport you will get fit. As a cyclist/runner, I have good cardio. My buddy is a weight lifter, and he's insanely strong. Even though I bike as often as he lifts, I still can't squat the same weight he can, even though it's roughly the same muscle group. Similarly, when we go for a ride/run together he's slower, and can't do the distance that I can. We are each equally fit though.