Inkmoth Nexus you want for sure, as for the other infect dudes if this is 1v1 its fine. If however it is multiplayer you are going to have issues when you are facing much stronger creatures. Personally I would only keep Ichor Rats, Skithiryx, the Blight Dragon, Blighted Agent, and Putrefax. The profilerate dudes are fine for the most part, only would really keep Viral Drake if you have some infinite mana combo for it.

Crystalline Crawler is kinda bad in comparison to just a Pentad Prism that fills the same role and does a faster job of getting there. Decimator Web is bad news for you because milling out a opponent will lead to reanimation no doubt forwarding their goal. Your contagion clasp does the exact same thing you are after in regards to poison counters and more.

Deadeye Navigator would be a good boon for you because with ichor rats you can keep blinking it out until both you and the opponent are at 9 poison counters then end the turn with atraxa profilerating for the win. Same thing with Kaya, Ghost Assassin although a bit slower blinking ichor rats in and out it does come with some nice disruption and a really cool trick with one of your dudes. If you attack with Putrefax and then blink him out with kaya he will only come back until your next upkeep meaning you don't have to sacrifice him at the end of the turn.

Mother of Runes can end up making a creature of yours unblockable or have shroud when dealing with removal.

Sword of Feast and Famine and Garruk Wildspeaker for a mix of ramp and evasion, also surprised you don't have Triumph of the Hordes

Finally you don't need 39 lands for a majority of edh decks especially for yours; you have enough mana rocks and dorks and in addition to that you have a very low mana curve with no mana sink aside from Viral Drake. you can comfortably go down to 34 and have no issues with mana.

This is a budget-y deck, so I don't want Inkmoth Nexus or Sword of Feast and Famine.

This is largely a themed, semi-casual, if effective, deck. Thus, I like having a respectable number of infect creatures.

I prefer Crystalline Crawler to Pentad Prism because it can start with more charges so I don't have to be as careful if/when I do need them.

I don't particularly want or have room for tricks provided by Deadeye Navigator or anything else. I've got combo decks that are fun (for me) and exceedingly effective, I want this to be an infect/proliferate deck, as pure as can be. Another reason why Mother of Runes is not included, though she would be effective in a deck that is more willing to go all-in and pay more attention to maximum optimization than to theme.

Triumph of the Hordes is alright but being a sorcery holds it back. Trample is cool but as most of my creatures already have infect, and are small/fast or have other methods of evasion already, it's not necessary nor ideal.

Finally, I have a (possibly irrational) preference to having 39 lands in my EDH decks. I feel a sense of comfort having that extra space to ensure my color ratios are within acceptable ranges, and find that land screw is more frustrating than land flood, so having those extra lands is, for me, an acceptable trade-off.

Add Sterling Grove.