IWP is probably the most cost effective. There is not much functionality loss and it not really any more complex than a regular filemaker layout to program.
Remote Desktop is not used to share files / network computers. Remote Desktop is used to access a computer such as your work computer from another computer such as your home computer.
Mac Mini Server is not required to host a filemaker databases. Your current computer may be able to handle hosting.
The hosting computer (Server) will require filemaker or filemaker server. This will depend on the number of users. Each client connecting to the host database will need filemaker to connect from a computer or filemaker go to connect from an iPad/iPod/IPhone. You will need a high speed internet connection for user to connect to the server from outside the local network.
The biggest loss of functionality for me will be not able to make PDF's and good printable lay-outs.
Also I only work from a lap-top which I travel with. So I would still need a permanent server.
What about have the databasde hosted remotely? Any experience with that?