I think peterix could be handy as he wants to spread dfhack usage.
as for 2 - I count here interface for incoming data from dfstats. something like REST or webservices. Can be plain php, too. User management and authentizatrion would be on fb side but one need at least store some attributes
which comes me to question: how will dfstats authenticates? fb username and secret pin set in website ui?
Well as I said I'm not familiar with the fb API, and my web programming to date is mainly centered around PhP and mysql. Now I'm not sure if there is a way to make a fb app auto update itself without a person running that app, basically if a person wants to update their info (ie they expanded their fort) displayed on their wall, can it be done with making them log into FB. As for updating the main stat page, it could be done every x min./hours using cron jobs. Of course that is just using straight php, and if the app itself ever grew, I know straight php wouldn't be the best choice.
I could personally bite the bullet expand my knowledge on just X language to use something like webservices, I'd have to view my options though with my current web server I use (I wanna learn C#, maybe that is a choice). Then use PhP to just display the page. Once again for me, this would be new water, but something I want and need to learn.
As for authentication, yea I think FB username (I believe fb allows that to be stored, or can use username to get their fb id, and that can be stored), and maybe a secret key, or they can use a separate password (hopefully most wouldn't use their fb password), if that doesn't violate something on facebook's side.