so the little short and Fat Ogryn and the Garden Gnome are "Squads" OK I have no clue what it should be the 40K wiki has no entries for "Garden gnomes"
so my playing ROSIGMA with the arbiters...first mission: a church...with Servitors, Panzer Garden gnomes, Hereteks, Ogryns, Sistas with Rocket launchers had to restart 3x because some starting locations where unplayable...but I had 1x Lascannon Sentinel, and a mastiff + Judge with Lawbringer and some penitents with Rocket launchers...can be done....second mission a ship with 12x !!!! Tzen Marines in January

I already got 1x Meltagun so the Sentinel + light chimera turrets, Rocket launchers + the mastiff!!! (I killed fuken chaos marines with the dogge) and the third mission: Munitorum sabotage was even more difficult but I somehow survived....
so there are no Ratlings and Catachans yet in the game...
I think playing ROSIGMA with IG is much much more easy then the Arbiters...Long las + Hotshot ammo and the Turrets will clean house again most enemies...the Heavy bolters (both handheld and HWP) + Kriegers + Commisars and later the advanced guardsmen are more them enough...plus one can develop and use the Airstrike...but the best weapon is the Missile launcher with Krak missiles...I had too many Base defence missions, and yes I had good experienced soldiers only in two...but I got attacked also in places where I had shite guardsmen..how did I manage...every Guardsmen had a rocket launcher + a Lascannon Sentinel + a Heavy bolter HWP...and I wiped the floor even with Terminators
and what I dont like in the whole 40k mod + Rosigma: the handheld lascannon is shite, and so is the mounted one...the Sentinel is working like a dream...but all other versions are "crap"
and what could be taken over to the IG from the Arbiters...well the sisters have a special Shotgun, so maybe ad a IG special Shotgun (Krieger Lucius Shotgun that can use also special ammo) or is the Ripper the IG special shotgun? (never equipped a human with one...will try) and also a SM shotgun? Deathwatch special space hulk cleaning shottie? also a silly idea...a Mastiff that the Commissar will use to deal with Deserters?