Upgrade Existing Wordpress Plgin

I own a wordpress plugin that allows me to deliver content to specific user and then generates and sends an alert email. In general it functions exactly as it should. I would like to add functionality to the Backend where I post the audio. I would also like to add some extra formatting to the emails that get generated. Finally, I want some style choices to be added to vary the way the front end display looks. Background - I believe this is a pretty simple plugin. It took the original dev about 2 hours to build from scratch. I had the code updated for PHP and wordpress version updates a few months ago. As wordpress grew, the plugin stopped working. It now functions at 100% What I want: (Ill try to be VERY thorough) 1. Backend Functionality: I want a few more options -Bulk uploading (select more than one file to upload at a time) -Currently it lets me add a note for EACH file I upload. IF I bulk upload many files I only need it to let me add ONE note. Even if I add many individual files, I only need to add ONE note for the entire post. -Bulk deleting (Tick boxes next to every file, "DELETE SELECTED" at top) 2. Backend Settings and Email it creates: -Send HTML emails WITH my logo at top -Add a "Login and Download" Graphic. I will create this -Currently, When I upload files and do NOT add a note it still places that empty field in the email. I want to avoid this -I want some formatting options (tick boxes, drop downs etc) for the email---chosen background colors, borders, rich text fonts etc **Either on this page or create a third area of the plugin -I want ability to change the graphics/logos later. Either tell me where on the server they exist or give me a GUI box to select one in media 3. Front end formatting (again on same area of plugin as above): ****These are NOT the most important features. I would like to know what I can do, what you can add. I need your guidance on what can easily be added or changed. -I want to have choices on what I make the front end look like. (tick boxes, drop downs etc) Fonts, colors, add graphic or logo per user, -I want ability to change the graphics/logos later. Either tell me where on the server they exist or give me a GUI box to select one in media -Page title user name at top like "Client ABC Download Area" -Remove the left column with the little file format icons