You might be more likely to get a response to the tableau question on a
tableau-specific channel. In general if it can pull in data from an
authenticated URL serving a csv/excel/html formatted file then it should
work.
If you're trying to setup a third party reporting system you may also want
to look at the data export tool https://confluence.dimagi.com/display/commcarepublic/CommCare+Data+Export+Tool,
which will provide more flexibility in terms of syncing commcare data to a
local database that should be easy to plug into other systems.