You'll get many opinions on the forums and its best to talk to the local CFRC and get the facts.
However, you seem to be in good shape. To improve push-ups, I'd recommend an all-around-body
weight program. Specifically, the bench press, inclined bench press, shoulder press, lat pull down,
and tricep curls are good exercises if orientated for strength training and will bring up push-up
counts relatively quickly.
Another thing to consider is over-all fitness. From one point of view, training just for
improving Express Test push-ups may increase numbers but puts less focus on other parts of
the body. In BMQ and in later operations, you may be climbing obstacles, running, marching,
carrying loads, working at a higher than normal tempo. Training to improve over-all stength,
endurance, and cardio is a better objective than just push-ups. In this regard, the training in
preparation for BMQ/military career is similar for men and women I think.
If you are unsure of how well you would do, try running 2.4 kms and time yourself. Perform
as many pushups as you can continuously, you've already done sit-ups, and compare it
to the CF Express Test requirements.
As far as miltiary couples being posted ot the same unit, it is and can be done but there may
be limitations. Better to ask the CFRC.
Good luck.