bug fix and minor modification on wordpress website

I need someone to fix a few things on a wordpress website. 1) The website has 2 main post types, one that displays artist and another one that displays songs and videos (we will call it project). The songs are being played via the Fullwidth audio plugin ([login to view URL]) and the video with some custom work I did on the site. They both have their own page, but I'm also displaying some projects on the single artist page. When editing or adding a project, there is currently a dropdown menu in each one of them on which I chose which artist page it should be displayed on. In other word I can link both post type together and display some specific project on an artist page. It was working well until a few days ago, when I added a new artist. I cannot find this new artist in the dropdown menu of a project and the projects displayed on an old artist page disappeared. I need to fix this. 2) The Fullwidth audio plugin also customized a bit to fit my needs, but for some reason, I can no longer change the basic settings of the player in the option pannel. All the changes (ex: put the player at the bottom of the page, disable shuffle, change height, etc...) are correctly saved, but aren't applied to the page. I would like to restore that. 3) The custom post type for songs and videos also allows me to include a link that will be displayed below the title. I have 3 post category : Single, Album and Video. When I add a link, it will automatically be displayed with the title "Get the song", unless it is a video in which case it is always written "video". What I would like to do is change the title of the link depending on the category. If it is a "Single", it will be displayed, "Get the Single". If it is an album, the title should be "Get the album". If it is a Video, it will stay the same as right now, it will be displayed "Video". 4) Each Artist have it's own header with a custom image on top of the usuel header background. There's a little parallax effect with those 2 elements. Currently, I manually change the custom image via CSS. There's a div on top of the usual background on which I change the background-image with the unique post-id css class. I would like to be able to do this automatically by uploading an image via the admin pannel. Thank you, Dominic