+1 Give the braking systems a thorough going-over. I helped a friend with a BD bike and virtually all of the cable housings required attention. Most were too long and the ends were poorly prepared. Once everything was tidied up they worked pretty well.

Since you are holding out services to the public I strongly suggest that you consult an insurance professional and an attorney regarding liability coverage and possibly forming an LLC or similar entity to protect your assets. A liability judgement against you can not only kill your business but can also financially ruin you personally.