How many anonymous users can I have?
The community edition/sandbox only supports Named users.
To use the Mendix App Platform (the portal, collaboration around requirements, etc. - NOT using the apps) do I also only have the limit of 10 active users per day?
The Mendix App Platform has no limits, the limits are only for the amount of users that can be logged into one sandbox at a time. If you have 5 sandboxes, you can have up to 50 users logged in (10 in each, you won't be able to have 49 in one sandbox and 1 in the other).