First of all, if they specify a counselor, you need to get a counselor. If they allow additional, unspecified recommendations, you can ask a teacher too. If they give you a choice, you can do whichever you prefer, but when a school asks for a particular piece of information, don't vary from that; it can only hurt you.
As far as the recommendation forms, I'm a university faculty member and have been writing letters of recommendation for decades. In most cases, I can write a single letter and attach a copy (or at worst make a few changes to it) to the form, sign the form, and I'm okay. If they ask very specific questions, I have to get those typed onto the form (which is getting to be a hassle now that I only know of one person on campus who owns a working typewriter!).
Finally, no, you can't preview the recommendations and use only the ones you want. In general, the letters must be given to you in sealed envelopes on which they have put their signature across the flap to prove that no one has opened it. In some, they have to send the letters in directly, bypassing you. Basically, you don't have the right to see your recommendations. If they want to give you a copy or show the letters to you they can, but they don't have to and you shouldn't ask. This is to make sure that the writers were not pressured into writing anything which wasn't true, and to avoid your being able to send them only the best letters (that kind of invalidates the whole process).