You can refer the documentation link JT2Go Mobile Help.
In documentation there is a note mentioned in 'Load Model' section
"Models may be loaded from applications that allow file associations on the devices, such as Microsoft OneDrive. Some applications that allow to you store JT files do not support launching files in JT2Go, such as Dropbox."
Not sure about iOS and Cloud. @RickV could give you the best suggestion/solution about your query.
In response to your questions (you are the second to ask about both of these in as many days).
Deleting cached files - we have added tasking to our backlog to facilitate this.
Cloud access - we are going to have to discussions with development and program management on this subject to determine how we may be able to address this.
Our latest release (4.0.5) now has the ability to delete cached jt files. From the Load File Dialog, select the Trash button to clear the files from the JT2Go cache.