The letter needs to come from the school because that's the charitable organization. But as a part of the school - thus an agent of the school, in some respects - the school might give you the authority to send the letter. This would be the same if you were an independent organization and a silent auction committee were getting donations and sending letters. They wouldn't send the letter AS the silent auction committee, but on behalf of the PTO FOR the silent auction.
As far as the different loyalty programs, you would have to ask each one. Right now, the school "owns" those accounts. Would they willingly give them up? If so, it's up to each company that runs a program as to if the account could be changed and how.
Since our PO is set up this way, (as a school committee) if a parent gives us a cash donation can we give them a letter stating the donation is tax deductable or would that have to come from the school?
Also, if the PO decides to separate from the school and file for a 501c3 and get an EIN and tax exempt status, would we have to re enroll in all the rewards/rebates programs we currently participate in (ie Kroger, Meijer, GFS?) or can we just change the EIN number on the account?
Without a formal application, your PTO is not technically under the school's tax-exempt umbrella in the 501c3 sense. You can operate as a committee of the school without your own separate 501c3, but that means you'll need to keep all your funds in a bank account set up by the school. Your proceeds would be included on the school's tax records, so it wouldn't really matter if you go over $5k. While this does simplify things a little, your group will not be independent if you operate under the school's control. One implication is that the shcool then owns your money. For a small group in a small school, that might be just fine.
We are a small charter school PO. Our school is a tax-exempt 501 (c) 3. I've been told the PO is umbrellaed under the school. Can the PO then go over the $5000 IRS rule of thumb or do we need to file for 501(c)3 status?