1. No. You have to by FM Pro seperately. get Advanced...
2. You have to buy connections with the FMS license.
1. FileMaker Server Development License
This special, test-only version includes all the features and functionality of FileMaker Server 14. Please note that the Development License only allows up to three simultaneous connections from FileMaker Pro and FileMaker Go, and 1 connection from a web browser through FileMaker WebDirect.
3. ESS connections (MySQl, Oracle, MS SQL Server) do not require FileMaker server
I am new at this too, but i can tell you what I have bought and have done so far.
I purchased FM Advanced and worked on getting my solutions to the point that I wanted to share them, then I purchased the FM server and installed it on a computer that runs pretty much only the server.
I am doing something similar to where I have about 20 construction crews working in the field and accessing FM by the FM go app on both iPhones and iPads. the big question to me was how many concurrent connections did I really need, because they can get costly. I have about 20 people using the solutions but they are not all using them at the same time. I ended up buying a "5 pack" of FMgo concurrent licenses and to date it has worked perfectly. There is a way to view how many times a connection was unable to be made because you reached your limit on FMGO users on the server. I basically just monitored it for about a week prior to buying the GO licenses.
Hope this helps
Your need for FMS really depends on how many people you have connecting. Development server is no good for regular use.
IF you only have a few people you could host the file from Pro Advanced and still make your external MySQL connections from Advanced. You will need to purchase the Actual Technologies driver for ODBC and set it up. buy at least the 10 connection driver. If you need more than the 5 connections you need FMS.
The FMS connections could be something you buy or I suppose you could buy it and pass along the cost to your customer. The connections are attached to the FMS license.
I have recently developed a solution using FM Go and FM Server. I own an FM Server license, but you'd be advised to take a look at some of the hosting solutions out there these days. I've subscribed to one that I really feel like is a great value, and has served my solution well - and I don't have to worry about the license, the number of concurrent users, or the physical hardware - so it's made management much easier instead of having to continually keep my own server.
I suppose it might get challenging if you have to do a lot of server-side stuff that they don't support, but for my uses thus far, they've done me quite well.