1. No idea
2. Maybe; don’t really know the product
3. Yes, but not simultaneously (same as usual)
1. See: https://www.dessci.com/en/products/mathflow/mf_for_framemaker.htm and use the contact information there. [Note: if you need to just insert good quality math equations in unstructured documents, then using Design Science's MathType may be a better option.]
2. If you use the "Style" editor (i.e. Design View) you create a visual that can be inserted into an anchored frame.
3. All Adobe licenses allow you to use your product on up to two computers (e.g. work and home machines), but NOT at the same time.
[Update] MathFlow costs are:
Add 20% to the total order for the first year’s maintenance (required).