Got it working. For those who run into the same issue, the Nexus 7 I have appears to be the newer version that has a different kernel/emmc. I followed the steps from this github using the updated flo boot and recovery files from here. Once I fastboot flashed those files and ran "ubuntu-device-flash touch --server=https://system-image.ubports.com --device=flo ----recovery-image=recovery.img" ubports booted to recovery and installed like it should.
Thank you for your help @Lakotaubp