The lamb represents the tardigrade.
The butcher's knife represents Lorca and Landry wanting to exploit the tardigrade to develop new weapons and armor technologies from it regardless of the cost to the creature itself. It's been imprisoned in a tiny cell when it used to roam free, and Landry is literally going to chop a piece off of it for testing.
They don't call Lorca and Landry the butcher because to do so would be to humanize them and open them up to the possibility of feeling remorse for their actions, when the point being made is that they've been so damaged by the war that they have lost their basic humanity and have become little more than weapons themselves; the knives. They are devoid of empathy or concern for this clearly sapient creature and care only about how they and the Federation war effort can benefit from it. The butcher's knife cares not for the lamb's cry. Lorca and Landry care not for the tardigrade's cries of anguish as long as it feeds the war effort.
Burnham can fall into the same trap at this point when she's discovered that the tardigrade can actually serve as the navigational system for the spore drive. She can simply exploit the tardigrade for the benefit of the war effort by painfully plugging it into the ship's drive systems, but she realizes that doing so harms the creature and is horrified by this fact and how her discovery has inflicted pain on this sapient being. So, because she is undergoing a redemptive arc, she decides to set out to reclaim her essential humanity by determining to talk to Lorca about finding an alternate means of navigating the spore drive. This carries over into the next episode when Lorca is captured and Saru now faces the same dilemma of exploiting the tardigrade for the purpose of retrieving the captain.
Saru, as befits his somewhat wishy-washy, non-confrontational, herd mentality character, hedges and chooses to exploit the creature despite Burnham's objections, causing it harm, but before he can do it again Stamet's takes the choice out of his hands and hooks himself up to the spore drive after injecting tardigrade DNA instead. But eventually even Saru makes the right choice (unknowingly after it's a moot point, but still...) thus allowing him to join Burnham on her redemption arc and not succumbing to Lorca and Landry's failing of losing themselves and their humanity (or Saru's equivalent) to the war.
Calling it a wolf instead of a butcher would imply that something is being hunted and this is just the natural circle of life. The tardigrade is penned in a small cell behind metal alloyed walls and forcefields. They cut into it with special armor piercing blades and stun it with gas and phasers. They hook it up to machines to hold it in place and pierce its hide to inject/remove DNA. There's nothing natural about this. It's a technological reaping.
As far as lambs not screaming before the slaughter, tell that to
Clariiiiiiiice. I wouldn't be surprised if that influenced their choice of title.
Without canceling it they should make it an episode by episode show. It looks nothing like a ship of that time, I would prefer an explanation be given for that rather than leaving it up to us to compartmentalize it all as making perfect sense. They can either call it a reboot or have a constitution ship shown in the original series that looks like one from TOS and have a conversation about why the discrepancies exist. There's a bunch of characters on the bridge that we don't know anything about, more character development needed there. 
