My understanding is that the forms themselves do not transmit - just the calculations (similar to an IRS transcript).  The IRS does not have the actual completed forms when a return is e-filed. 

Virtually all forms are eligible to for e-file. Even those that you need to do in a pdf and attach to the return can be efiled. There are a few exceptions and they will be noted in the diagnostics before you file and you may have to paper file in that fairly rare instance.