InfoPath Dev

I dont know what features aren't include in a InfoPath web form vs a InfoPath client form, sorry.

Yes, you have to have a data connection established.  To create this, in InfoPath Design mode, start from the DATA ribbon, Click the Data Connections icon.  On the pop up click Add, create a new connection to: Receive data, Next > select SharePoint Library or list. Next > paste the URL of your share Point site.  Next > ...

As long as a correctly understand what you want to do.  The easiest way to do this from InfoPath 2010, in design mode, Make sure your Fields are visible, and your Rules Manager is visible.Highlight your  <Field 1> on your main window.  In the Rule manager pain, select New, the action.  Under the section ‘run these ...

In InfoPath 2010 I have a nested repeating table (one parent, one child)…Each table is bound to a separate external data connection (SharePoint 2010 List) so that I can view data from the respective lists. The Parent Table filters off a field from Main (myFields) (ie if office_parent_repeating_Table != office_main, then hide control), that works ...

Are you using SharePoint 2010?