Multiple DB Question

[Total]

I have been searching around and reading other similar threads about combining multiple databases into one, but I just wanted to be sure about a few things before I look for someone who can do what I need. I want to be sure I know what to ask when looking to hire someone?.. in the near future?..


DATABASE-1
I have an older large vB3 (earlier version of vB3) database which was used up until a certain point. I would like the content and users from this database to be imported into a new fresh install of vB.

DATABASE-2
I have a current small phpBB database which started when the old vB database ended. I would like the content and users from this database to also be imported into a new fresh install of vB.

CONTENT PRIORETY
Some of the old vB database and the new phpBB database have the same user names, but I am really only interested in saving the new phpBB users if there was a conflict. Same goes for any conflicting/same forum content itself. New phpBB database gets priority.

CONCERNS
One of my concerns is that our current phpBB forum is actually a phpBB module for phpNuke so I?m not sure what needs to be done to convert it to vB. Would it need to be converted first to an original phpBB and then to vB, or just strait to vB, ect.

My other concern is with the minor differences in vB versions with the older vB database being an unknown or earlier version of vB and the current phpBB database being converted to vB which (I assume) would be a newer version of vB3. Or is this irrelevant?



Anyway?.

Is what I am looking for possible?
What would some real concerns or hurdles be?
Is there anything else I should know before looking for someone to do this?


Thank you in advance for any input