I generally try to kill stuff via Poison to avoid the secondary effect of Poison Revenge, so Lucario generally isn't going to boost Toxicroak's damage. In fact, it would technically reduce it by 10 under ideal conditions. I could be baited into a damage KO by my opponent sending up a regular Garchomp C, but that act by my opponent would be followed by a Judge + Psychic Bind (if possible) from my end of the table.
In addition, unless my opponent can get a Poketurn (harder than you think midgame, -2 or -3 and Hand/Power pressure), Toxicroak will potentially be "trapped" active 87.5% of the time (Tri Poison Flip negating Leap Away, Scorpion Grapple Paralysis negating Leap Away, or just a tails on Leap Away: 1 - (.5)^3).
As stated in the article, I really haven't played against Machamp much with this deck. In the one game I played, the opponent got one Machamp out, but was unable to do much else due to my constant hand disruption, Power Lock, and damage-stacking Poison. A Heads on Tri Poison can often force a Level Up or SSU. Some/Most Champs run BTS, which gives B/D a helpful - but not necessary - boost to both speed and recovery. Against Umbreon, bad prizing would seem to finally become an issue, as the best counter to the fox (?) in this list is using Tri Poison followed by a Scorpion Grapple from a Drapion non-x.