Will go over this in more detail later, but for now I'll just comment on the weapons:
Lancer Mk2 st 4 ap 5 range 24 assault 2 Chainsaw counts as close combat weapon
Str4 AP5 is fine, I'd say assault 1 or rapid fire, chainsaw I'd possibly make rending, 24" range is fine.
Hammerburst strength 4 ap 4 range 30 assault 2
I would make this rapid fire.
Lancer Mk1 st 5 ap 5 Range 18 assault 2 Bayonet grants the wielder plus one strength on the charge.
this I would make assault 1 regardless. I think it granting +1 attack would be fluffier.
Gnasher Shotgun St 5 ap - Range 12 Assault 2
I'd make this dual profile - Str6
AP- Range 6 Assault 1 /
Str 3
AP- Range 12, Assault 2.
Sawed Off St 6 ap - Range 6 Assault 1
This I would make Str8
ap- range 3, Assault 1. Ingame it'll instant kill damn near anything - if you could kiss it.
Long Shot St x ap 3 Range 36 Heavy 1 Sniper
This is fine.
Scorcher Strength 4 AP 5 Range template Assault 1
Also fine.
Chaingun Strength 7 AP 4 Heavy 4 Range 30 Rending
I'd say range 24, Heavy 3. dropping rending.
Missile Launcher
Frag St 4 AP5 Heavy1 Blast Range 48
Krak St 8 AP3 Heavy1 Range 48
They don't have a missile launcher - I'd make this a Torque Bow - Str8 Ap3, Heavy 1, Rending, to fill in the rocket launcher place.
Vulcan Cannon Strength 8 AP 4 Heavy 2 Range 24
This is like a chaingun on roids, so need 2 man team, str8, ap4, heavy 4, range 30, rending (like you had the chaingun initially

)
Mortar Strength 8 AP 3 Heavy 1 Large Blast Range 6-36
I'd say small blast, heavy 3.
One Shot Strength 8 AP 1 Heavy 1 Range 48
I'd make this a Lance or maybe Rending
Hammer of Dawn St 10 Ap 1 Blast Range 36 Heavy 1 scatters 1d6 but does not minus ballistic skill. It can only hit the top of buildings and ruins.
I would make this Str9 Ap1, Heavy 1, range 36. Special rule - you choose a start point and end point within 6" of each other, then roll scatter for each. everything in a line between the two resting points gets hit.
Snub Pistol St 4 AP 5 Pistol Range 12
prolly fine.
Boltock Pistol St 5 AP 4 Pistol Range 18 pinning
I'd drop pinning from thisun and make the Gorgon Machine Pistol that's str3, 12" or 18", pinning