i think you are mixing up things
Odin requires your device to be booted in download mode, not recovery mode. if you are in twrp you must leave revovery mode, you can reboot into bootloader from twrp menu. other method to boot into download mode is button combination Volume Down + Home + Power. then select Continue with Volume Up
SeAndroid not enforcing is just a info message which tells you everything is all right. for full access to partitions TWRP requires kernel which allow setting selinux permissive. if SeAndroid is enforcing it would prevent TWRP from working properly
side note: whatever you want to flash from Odin, you could do from twrp command line, too. twrp has full access to all partitions and skilled user can raw write partition images with adb push or dd