"Hopefully" is more impersonal than "I hope". It is a more general type of hope, rather than a personal feeling on the part of the speaker. It's more similar to "Let's hope..." "Hopefully" is also more optimistic than "I hope". If he'd said "I hope it'll bring in some information", this could imply a level of doubt. "Hopefully" implies a greater degree of confidence. It's not especially colloquial these days. Many years ago, teachers used to disapprove of using "Hopefully" in this way (for reasons too flawed and tedious to mention), and told us to use the very formal "It is to be hoped that....". Thankfully - another adverb use they disapproved of - that doesn't happen any more.

Both "hopefully" and "I hope" are appropriate here and are equivalent. I would say it is common to start a sentence with, Hopefully. To my ear, "hopefully" at the start of a sentence isn't colloquial.

Yes - you are using it to modify the whole verb phrase. If you just attached it to the verb here it would imply that "it" will feeling hopeful as it was bringing the information in. I hope and hopefully are often interchangeable, but the subject has to be "I" and not "they" or "we". Used at the beginning of a sentence it is assumed that "I" is the one hoping, but in another context it could be ambiguous who is hoping.