If you want to run backups using AOFO, then separate the jobs. Using AOFO with SQL is known to cause issues.
Splitting the jobs in this case is recommended.
I suspect that to back up your SQL logs every 15 minutes, you will have to look at creating a job for that, selecting the option to Log No Truncate - Back up transaction log - no truncate, and schedule it to run every 15 minutes from x-hour to y-hour, with the full backup running at the end of the day during your backup window.