InfoPath Dev

I personally disable the save as button (Tools > Form Options) in the toolbar at the top of the infopath form.  I add a button from the toolbox, tell it to do rules & custom code (even though I'm just using rules), create a rule on it to submit it to the sharepoint library, and name the button "Save"

Any values that were entered and saved/submitted to the SharePoint library prior to the property promotion will not populate.  If you open a form and submit it to the your sharepoint library now you should see the value of those fields for that form.

Yes, InfoPath can do this.  This is called a "Template Part".  Open Infopath, choose design a form template, under "Design a new:" select the radio button next to "template part" and choose blank.  Then when you're done designing it, save it of course.  Then when you're designing a form ...

I know this is old, but I found a quick solution.  Open your form with either notebad or visual studio, etc.  (if it's on a sharepoint site, click to download a copy first).  At the very bottom of the XML remove everything starting with:  <xdado:originalDataUp to the end of the original data close tag; leaving the ...

 Change the rule to does not equal 1

That's correct that you don't use sum()  (sum is for columns, like in a repeating table --- you only enter one field for sum).  Are you typing in "field1" or are you clicking "add a field" then selecting it?

Right click your first check box  Click Check Box Properties  Data Type:  True/False (boolean)  Value when Cleared:  0  Value when Checked:  1  Click OK  Repeat for all check boxes in the group you wish to validate  Click Design Tasks  Click Data Source  Click to ...