merging extensions

I want to merge some features of 2 extensions: Dropfiles (from [login to view URL]) and Quicksell (from [login to view URL]) and also change/add some other features Here are some of the features I want: 1 - if file type is pdf, then select in a check box to define if it will have watermark and password protection; if so then everytime a registered user downloads that file it will watermark it with his email and password protect also with his email (using the quicksell extension, or in any other way if more simple) 2 - tags management: add the possibility to create, edit and delete tags, so that when uploading a file or editing it's info the tags are selected from a list of tags (and not typed); 3 - language management: add the possibility to create languages so that everytime a user uploads a file he can associate a language; 4 - in the frontend form used to upload the file, add a title (text field), tags (any form field that allows the user to select multiple tags) and a language field; 5 - when uploading a file, either in the frontend or in the backoffice, replace it's filename with the title (erasing the spaces);