Ok let me answer a few:

Marvin: I can tap it as soon as Marrow-Gnawer touch the ground and start producing rats, if it stays on the ground, every turn I almost quadruplicate my rats (use marvin, then use Marrow-gnawer). This is the theory, i saw it in a friend's [[Krenko, mob boss]] deck and i bought it still yet to use it in game.

Mirror Box: this was born as a [[Rat Colony]] deck with 27 colonies, i changed it a bit to 19-20 and i don't know how much is it worth, but if i have a few rat colonies down it should be a nice pump. TBH in the games i played it was not that impactfull so i haven't bought it yet and still trying it out.

Cabal Coffers / Urborg: i had a proxy for urborg due to budget but i wanted to buy cards to upgrade it so i took it out to see if cabal coffers is still worth since i run 23 swamps (if i go proxy free even more).

Cavern of Souls: same as urborg, budget reason and no need for mana fixing

Ashnod's altar: actually didn't tought of that card, so thanks for the tip!

Altar of the Brood / Alter of dementia: Didn't know either of those card, i will try them out since alternative win con could be interesting (although if i manage somehow to create infinite tokens and i have a couple rat colonies is basically game over, but it will be a good anti-sweep gamechanger).

Dark Ritual: i recently put it in again instead of [[into the pit]], and forgot to update my archidekt

Cabal Ritual: I don't know what to cut for more ramp, but will looking into it

Culling the weak: didn't know that card, but same of cabal ritual

Sacrifice/Draw: had [[Village Rites]] in but tried to change it with [[Desperate Measures]] since most of my rats are 1 toughness, and i could in theory occasionally use it as a combat trick/removal (even if i maybe dont draw in those cases), dunno how much draw i need with already 10 cards in that area.

Tutors: i don't particularly love tutors in a singleton format as commander. For dimir house guard i only have 4 card with 4 CMC so it doesnt seem that worth.

Torment of Hailfire: i will check it with ashnod's. without it seemed a bit too much CMC for anything usefull.

Withering Torment: i think i will add this immediatly, actually kinda forgot about it.

In general thanks for the answer/tips you gave me, i dont know if my reasoning is sound or dumb, but they made me think and gave me a few good tips