Applying to several faculty positions within the same institution
I advise against applying to all open positions at once. Not only are you likely not to match the criteria for many of them, but you are also not interested in accepting the majority. By doing so, you just add to the workload of the hiring committee. Furthermore, you decrease in a way the value of your applications, as you should be striving to emphasize how you are the best fit for that particular position and that gets very hard when trying to apply to many different positions. You'll likely end up with mediocre applications everywhere or worse with the same application everywhere.

Typically, there is one position (as you say) which you would like to get and are probably best suited for (depending on your qualifications). So I suggest you narrow down the open positions to at most 2-3 where you would most enjoy working, if you insist on having a safe option, and try to write strong applications for all of them.

Finally, I don't see how a "preference statement" would help you. If you get your desired position, then it is not due to your preference, but because you had a stronger application than other applicants. If you, however, fail your best option, other options might see it as a negative thing, if you stated that you'd prefer to work at some other position and only failing there, apply to them. So, the idea is to apply everywhere with the same zeal. That's also why you have to narrow down your options, so you can accept any outcome, if needed. If you are not comfortable with that, it means that the options aside your primary are not attractive to you and I would refrain from applying to them (assuming of course you are not in a position that you have to accept any job). In the case you get accepted on more than one position, you are of course free to choose.