Team Rocket Leader: Arlo Guide

Team Rocket Leader Arlo - "It's time to learn your place in the world"
There's nothing here really, unless you want a shadow shiny wobbuffet. You can get way more value elsewhere from your Rocket Radar.
Pokemon lineup
There's not much going on here. Shadow Wobbuffet unfortunately doesn't even fill a niche.

Team building recommendations
For the Team Leaders, it's important to work on strong team building a bit more, as they definitely pose more of a threat than most of the grunts. For this reason, we're going to look at our counters less on an individual basis and more based on their role within a team. This team structure isn't mandatory to win, but at least some degree of planning will help tremendously.
Lead
Fury Cutter and X-Scissor are great at dealing with shields early on and also has a good matchup against Slowbro and Alakazam.
Second slot
Having good matchups against Steelix and Scizor with Fire Spin as a fast move to gain energy quickly and Scorching Sands for coverage against Alolan Muk.
Third slot
Mamoswine is here just in case Arlo has a Crobat. If you have one with a second move unlocked you can give it Bulldoze for coverage against Alolan Muk.
Good substitutes
Arlo is vulnerable to Electric types in his second slot and should be exploited. Except for Steelix that completely walls them. Now that Raikou has access to to Aura Sphere, it can threaten Steelix too!
Heatran can replace Entei, but it's almost required to have a second move unlocked if you have Magma Storm on it. It needs Earth Power for coverage against Steelix and Alolan Muk.