Your MIDI arrangements are fine for what you seem to want, although you might want to use the Analog Four’s MIDI Thru instead of its MIDI Out; there is no need for any additional MIDI routing hardware.
Do remember that as of OS 1.40 the Analog Four can also store tempo per pattern, and it has a Song Mode.
If you are live sampling then there may be some advantage to the Octatrack being the clock source. The OT also has the most developed song (Arranger) mode.