Edge Gateway with 2FA?

Yeah you are nearly correct on this one, the "Edge Gateway" product is purchased as a single module, although you cannot stack this with other modules on an appliance, as it is already a combination of APM+WA+WOM (unless there is anyway of having 4 modules on a BIG-IP platform).

The bundle itself does not include LTM as it is targeted as a remote access solution and you cannot add LTM (for the reason mentioned above) so you are required to use a "Webtop".

If you require LTM they you will need to stack this alongside the APM module, this also creates another option (not included in Edge) that allows you to directly assign the "Access Policies" to the LTM VIP instead of using a Webtop.

Let me know if you need anything else.

Craig