Hmh...
First of all - you've got toanswer yourself a question - "what is Oktober Guard?" Because this, will determine the shape of vechiclews.
As for me 0 I see OG as a group one step higher than Spetznaz. So - they operate in small, yet versatile and efficient groups, base more on mobility, surprise and excellent tactics. If so - they don't need supreme firepower, ALTHOUGH it would be welcome from time to time.

As so - they would rather need fast and quite well armoured personnel carrier, than a heavy tank.
All your concepts are good and functional for them (maybe the less functional is AA gun, as it is only double barelled). I would suggest - why not trying to make a multifunctional vechicle? If all weaponry don't require permanent attaching - you could make one chasis and 3 interchangable weapon systems. This would make a great multi-purpose vechicle in my opinion.
Although, I would leave this grenade launcher (or is it a machine gun?) in the front of the vechicle, so you will have additional extra space for other weapons.

And If we are talking about a single project - I would choose the first one. But that's only my opinion

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