As an Academy we don't specifically promote competition but if YOU want to enter competitions (which can be a lot of fun) we will fully support you with appropriate training and probably come along to give you a cheer.
Competitive Push Hands ('PH') training is not part of our standard curriculum as I feel that it's inherently competitive nature can get in the way of learning the specific skills that make Tai Chi so valuable both as a health art and as a means of self defence. However if a student wants to compete in PH competitions, again we will be happy to train them and go along to cheer them on.
I have competed in both Kung Fu and Karate competitions, and I have watched many Tai Chi and Push Hands competitions. They can be great fun and a way to test your skill. However, there is no emphasis on competition at our Academy and it is completely OK if you never give competition another thought.
We have had students from the proverbial 80 pound weakling through to power lifters. It is fair to say that excessive weight training or body building may conflict with some of the aspects of Tai Chi but it is your body and only you should be the judge of what training you want to do.
Yes. Indeed, as long as you are fit enough to take part in aerobic exercise (gym classes, running, whatever) I would strongly recommend it. Tai Chi will generally not improve your aerobic capacity (there are some exceptions to this, especially with people who are unfit or recovering from illness) so to add this to the mix of things that you do to keep healthy - things like getting enough sleep, eating sensibly (some of the time), and etc... - can only be of benefit.
Yes. It will take some time to become an instructor, especially if you would like to be recognised by the Tai Chi Union For Great Britain (which we would recommend). Assuming that you train twice a week and you practice at home then you should be able to become a basic level instructor within two or three years.
My answer is yes. There are instructors who would say no, but I've never understood why. You wouldn't expect a school to say you can't learn two languages or two science subjects so why should learning two martial arts be any different.
However, it would probably make learning more difficult if you started two or more martial arts at exactly the same time, I'd suggest doing one for six months before starting the next simply so that you have the basics memorised.