[(E)]

As to the alien population, the numbers I picked out were based loosely on what I eyeballed as a reasonable living population for the Arc. That said multiply it by ten or a hundred or more for cold sleep etc. Feel free to change it completely if that works better.

Answer 44 Weapons (partial answer)

Cased slug throwers
For various reasons, some of which have little to with the physics of weaponry, some manufacturers continue to produce cased firearms. In general terms newer cased firearms have larger calibers to cope with modern armour. The increased calibers are usually combined with recoil compensation systems that make the guns bulkier and heavier as a result. "Victory arms" is one of the leading producers of cased weapons and produces both the "Grace" and "V-25" rifles, the former is a bullpup semiautomatic that fires a round comparable to the old .50 browning, the V-25 is a multiple ammunition 25mm that relies on having a range of specialized rounds available.

Caseless Slug throwers
In general caseless weapons use the benefits of Exotech to manage heat buildup better, this has allowed an increase in rate of fire. The larger magazines this has necessitated results in a bulkier and heavier weapon. The Red Star Armory has led the field in caseless technology for some years, based in a Russian/Nigerian city state in the UMCS they make the XK series caseless weapons. The XK-42 "Wrath", the XK-38 "Rage", the XK-27 "Fury" and the XK-102 "Berserk" are the most well known and frequently seen, several other manufacturers make similar versions of these popular weapons. These weapons are frequently used with "stacked" magazines that are loaded with a wide assortment of ammo types.

Gyrocs
A range of gyrocs exist, Beretta has a solid reputation based on several excellent models.

Laser weapons
Favoured by several groups due to the not relying on a "slow" projectile, a problem in some of the long range combat situations away from a planet's surface. Phillips and HG are the two big players in this field. Sniping weapons and Machine gun equivalents are the two areas that lasers seem to be dominating. Emplaced laser weapons are common as their effectiveness is greatly improved when hooked up to a reliable power grid.

Recoiless
Several recoiless rifle style weapons are used by stronger than human combatants.