I don't see why you would automatically be in "a world of hurt". Yes, you might be if you were to suddenly roll it out organisation wide without any testing, but no sane IT department would do that. This is why you have internal test groups and pilot groups. Once you identify the limitations, you scope out the missing features/issues, engage developers if need be, or look for alternate solutions. No one needs to get hurt.
No, but that's only because I hate Excel. But I'm sure developers who don't hate it but also appreciate FOSS solutions might be interested, if the pay is good.
Access = LibreOffice Base
Visio = LibreOffice Impress
Outlook = Schleswig-Holstein already switched successfully to Open-Xchange and Thunderbird, I've not heard of them running into any major issues with this setup.
I find that highly unlikely given how much commercial agreements with MS costs.
But if that's the case then they should either look for a different COTS solution, and/or change their business workflow.
And in the event even that is unfeasible, then just continue to keep a few windows machines (maybe convert them to VMs or VDIs for ease of maintenance) for the few users that can't be migrated.
