Hi. Sorry for the late reply, I was awaiting the release of 2.5 to answer your questions/post but I thought I would go ahead and follow up here since its running a little behind.
First, we do have many of the features you requested on the Dynamic Forms 2.5 Roadmap which is currently in development and should be released soon.
Here are some specific responses to your thread:
Allow SQL Driven Hidden Fields. -Yes this is addressed in 2.5. This already exists in Dynamic Registration and has also been added to Dynamic Forms for upcoming release.
Have a visual representation of a hidden field on the form while in edit mode (minor, if possible). -This will not be in the 2.5 release but we will see to add it in an incremental release later. The problem here is that you would want to make sure its a hidden field to make sure that its testing/working properly and so forth.
Open up the "Initiation Response" field for Question Events for manual entry. - I am somewhat confused about this, is this because you might be using a SQL Query for the field? Since the initiation question is not allowed for fields such as textbox fields I am not sure why free form would be necessary (I guess for SQL Queries on fields it might be necessary though). If you need a work around for this now you could manually update a table in the database for the initiation response. We also have many new client side events coming up which you can check out on the roadmap.
Provide for Short names on Custom HTML fields so they can be distinguished from one another. -This is addressed in 2.5 release.
Allow for Question Event triggering on hidden fields. - Hi. Well the problem here is that hidden fields do not typically 'trigger' anything, in other words there is nothing the user could do on a hidden field that would be able to present the a postback etc... I can see the benefits though if you are using this in conjunction with the SQL Default (so that way whatever is pulled in would then be able to be used upon initial load for question events) or I guess if you were passing something in from a querystring or session variable. I am not sure this will be in 2.5 release but I can see how this could be used and it shouldn't be very difficult to add.
Question Events should fire if the values are auto-set (such as retrieved from a query string) not just user selected. - This should already be able to function this way?
Sorry for the late response. Let me know any feedback you might have on these comments as we are right in the middle of development on the 2.5 release now.
-Chad