My own opinions about the rifle. YMMV.
The size of the rifle has to be such that it's lightweight, compact, reliable and accurate. In this regard, I think @EyeR and @Thymeless are right on the money: the bullpup fits the bill perfectly.
Furthermore, I would suggest that the service rifle Asgardia carries should be psychologically intimidating to further dissuade criminals. This doesn't necessarily mean usable rifle features, however (although the PS90 laser sight is intimidating to begin with). For example--dark blue, black and grey have been proven to be psychologically intimidating colours, so the forces could just paint their rifles black and grey. In this way, our defense forces might not even need to fire a shot. If a low-level criminal sees intimidating-looking security/defense/police officers walking around with bullpup rifles, they're definitely going to think twice about breaking the law.
I did have another suggestion, though: why doesn't Asgardia just design it's own damned rifle? ;)
Here's a video of the FN-P90 in action, for fellow gun nuts.