"Who gets to decide what is religiously exempt when bills are being passed and laws put in place concerning religion?"

Right now YOU do. It starts and ends with the people's house. That is, the State legislature, who creates laws. Those Religious and Philosophical Exemptions were encoded in law many years ago. It is your job (and all of us) to keep those laws in place and to also improve them, to which ALWAYS needs to recognize the SANCTITY of our body. If we are made in the image of God, there is indeed sanctity of Him within us. Sanctity within us gives us the Right over our own body and control over our own health to pursue happiness.

The School have to follow the law. Those Statutes should be looked up for any further insights for filling out the proper paper work. It appeared to me that the form you fill out is all that is required. Ensure you provide the correct information. And they must oblige you of your Right. That ought to be the end of it. I thought I read that Colorado requires you to do this each year. I thought this was odd, but very well, so be it.

"... anyone making laws in a state or mandates at a place of business that require you to have a “reason” for your religious exemption."

Where does CO law state you have to show a "'reason' for your religious exemption"? I didn't find this in the law. Go back and read for yourself. Put only relevant information down. Nothing more. Being concise is being short and nice. Less is more. Do not write information not required.

"Within my religion, my personal religious belief might be because I interpreted a certain verse or passage a little differently than the person next to me and that’s my right."

This is all irrelevant. A philosophical objection is also recognized by CO law. Short answer:

"As provided by CO State Law, CO Statute Rev. Stat. § 25-4-902, 903, I strongly object to being vaccinated based on my deep personal belief."

If it is a religious objection to being vaccinated:

"As provided by CO State Law, CO Statute Rev. Stat. § 25-4-902, 903, I strongly object to being vaccinated based on my deep religious belief."

End of story. The above is all you should need to write. Have a notary public sign the letter or form when you sign it. Make it look official. Verify the CO law for yourself. Ask other people who can add insight.