At first, when i've seen this core, i haven't liked him, but after playing with this, it's so cool!
So first, i think i have to explain all the choice of the mons:
-Steelix+Weezing is an amazing core, they check so many threats like CB Sawk, Scyther, Klinklang & cie!
-Lapras, because this core is pretty weak to the water spam, i've wanted a think who can defeat all the waters and just take easily Hydro Pump/Scald, so water absorb Lapras was the best choice in my opinion. Also, Lapras act like a cool wallbreaker, it's so hard to switch in against him.
-Magmortar, after giving a look at this core, i've noticed a huge weak to the fire type, and sash Vivillon was a threat. Magmortar looks like a good idea to check this. And it help Lapras to defeat the Grass-type.
-Hitmonchan, I've wanted a think who can help magmortar, lapras, and keep steelix's sturdy without giving me useless weakness and who have a good offensive pressure, so Hitmonchan looks like the best choice when i've builded this.
-Sceptile, the team was so slow, and lack of a good win condition. I've choose to play SD Sceptile to cover these two ideas.
Now, spread/sceptile's set:
-Steelix avoid the 2HKO from Tauros's Fire Blast, and with these Def EV's it avoid too the 2HKO from EQ Piloswine, which is cool.
-Weezing outspeed Rest talk 8 EVs speed Malamar while it's a huge threat for the team, so weezing can wow and then taunt him to prevent the rest.
-Lapras outspeed Lanturn and can punish him with Freeze-Dry. And 4 EVs Def to come one more time on the rocks.
-Sceptile's set allow him to deal more easily against threats like Pyroar, Scyther, Magmortar, Archeops, Jumpluff with natural gift rock, Natural Gift also allow Sceptile to use Unburden whenever it's needed
Thanks for reading~