Since you are keeping water levels in the tray rather constant, you might not need to mist as much. As for watering requirements, it varies on many factors. If you are a little worried you can check by poking it. Insert a twig, or wooden chopstick, or other long and slightly absorbent tool into the soil until you feel that tool has reached the bottom of the pot. Wait a little, and remove it. I am sure you have probably figured out the point of this, or read it somewhere else during your research conquests.
It most certainly is not a "dud", which I assume you mean to say "broken". "Bad" is a subjective word, and you would need to decide that for yourself; so I won't go into that. However, it is living and therefor not "broken". You can care for it, shape it, train it, throw it at a passerby, whatever you fancy.
Thickening the trunk can be done through many techniques. Do a little research though, to find what would suit you best. Planting your tree directly in the ground is often recommended, but this option can be limited by things like your hardiness zone, or space. I live in an apartment, and don't have a yard; which makes it hard to grow things in the actually Earth they were born from.

Do some research on your plants species, as well as general bonsai techniques. You will certainly find a plethora of information on the internet, but also at your local library or book store. Talk to people at some local nurseries.

I hope you enjoy your newly found tree, and find the answers you seek.