Converstion of a phpBB system and a simple guestbook to bbPress

I am running three discussion forums on a slightly old version of phpBB 3.0.7-PL1 on MySQL. They over 50,000 posts combined. User registration is not required so people use any names they make up. I want to have everything imported from phpBB maintaining the original forum and topic structures into bbPress, including taking whatever names people used when posting. I also want the attachments carried over into the new system (photos, audio, etc). A great bonus would be if the count of replies and views can also be maintained but it is strictly not required and can be quoted for as a separate module. There is also a very basic guest book that needs porting into bbPress under similar conditions as above for the phpBB. It uses PHP and MySQL and has no attachments, one forum, one topic and only one moderator account. There are about 42,000 posts in it under different made up names with no registration required. In all the cases above, it is an absolute must that there should be a way of using .htaccess 301 redirects in order to allow anyone following an old link to still get to the exact topic and the page. This is also important for search engines not to lose what they have indexed on the forums so far. This means the IDs of the original posts must be maintained. Expected output is a script I can tell what database to import from and the destination database in WordPress. I want to be able to specify how many records to import and the starting record number so as to avoid overloading the server.