Custom Letter of Reccomendation

I volunteer at my local hospital for a few years now and since June volunteer at the renal transplant department. I do have a passion for volunteering so I am going to emphasize that in the essay.

Out of the blue my other supervisor (one at renal) asked me which college I wanted to attend. We talked a a bit and she offered to write me a letter of recommendation. I was actually really surprised she brought it up because I didn’t plan on asking her until the next week. She added that she will write it a certain way and going to get employees and the head doctor to sign off the letter.

I told her i wanted to go to Northeastern and that that school was big on volunteer/ internship/ work. So perhaps she could write one in that direction.

My questions are,
For a school like northeastern should I get a letter that emphasize the work I put into that department or something about my “versatility”.

Is it okay for a bunch of people to sign off the letter or maybe better for supervisor and doctor?

If the letter is about work experience, should I just send that to every college because it is demonstrating a passionate trait.

Lastly, I work at two hospitals. I am asking my supervisor in both hospital A and B but also the renal department of “A”. So all my letters will be about volunteering. Is that going overboard and repetitive? I know some schools want EVERYTHING.

Thanks alot for reading and helping me out. Its not even october and I am loosing sleep over the process!

sorry wrote this in wrong category sorry about the troubles mod

someone from my school got his friend to write a letter and he got into dartmouth