Framework Order - Question?

Hi Experts,

I have few questions on SAP Framework Order PO Doc Type FO and Item Catg B and Acct Assig Catg K or U. Please help to clarify.

1. Can we use both material and text items?
2. Understand GR is not required for FO and only MIRO, Where and how this is being controlled?
3. I made a GR Based Inv Ver check box in Vendor Master and then i created a FO PO but still it did not enabled that in PO.
4. I set a limit in FO PO as $100. But system still allow me to post more than $100 in MIRO. Is this an issue? How this can be controlled in MIRO. But i did not select any no limit in PO.
5. I set a validity period in FO PO. But system still allow me to post MIRO out of validity date. Is this an issue? How this can be controlled in MIRO.

Thanks

RS