This is how I get mobi files into the ipad>reader app, without itunes, cloud or calibre:
I use the FileBrowser app to connect via lan to my mac and then transfer any number of files across to folder/s in the FileBrowser app.
https://itunes.apple.com/au/app/file...er/id364738545
From there, select what mobis you want to read and use the 'share file' option in FileBrowser to choose from the ipad's available apps that read mobis. I prefer to read them in the tiReader app.
https://itunes.apple.com/au/app/tire...r/id1276508285