Hi. I agree with Sue that working out prior is not the Zone friendliest thing to do, but with your options, that's the way I would go. I'm not even taking into account that prior to eating coming from a fasting state is SUPPOSED to burn fat quicker (I've read the arguments and the jury is still out on that), but your choices of exercises are good, and they aren't done heavily enough to cause a lot of catabolism. It's going to stimulate your metabolism. I would suggest a bit of a change though. I'm sure you can find a broomstick or a pvc pipe or a wooden dowel to put on two chairs. Lie beneath it , grab the bar/dowel and pull your self up. These are modified pullups, easier, yet beneficial. Do 10 pullups, 10 pushups, 25 squats, 15=20 of an ab exercise of your choice, one right after the other. Do 34 round of this, then finish with about 10 mins of some cardio of your choice to cool down. The whole workout won't take over 20 mins, Shower, eat beakfast, and go to work. What I do is to have breakfast all prepped up the night before, so all I have to do is slap it in a microwave, unless I'm doing oatmeal, and that only takes 10 mins stove top.
Best to you