Let me take a stab at your questions:
1. A Masters is usually for people straight out of a BA, and since you have worked for some years, it seems an MBA is more what you need.
2. Thant stinks!
3. Good. All of them are excellent programs for your goals
4. This will depend on the strength of your application, mostly. IF you are reapplying next year consider retaking the GMAT
5. Hard to say. I'm no visa expert, but from what I have seen "on the ground" nobody is refusing Visas to people who work for huge companies. But who knows? Speak to people in England...
Other than that you might consider Oxford and HEC (But GMAT is a bit low)
Best of luck!
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