Since we're not voting in this thread, I just thought I'd share my thoughts on the nominated mons.
~iss's Porygon
Whilst I agree that Porygon has decent team synergy, I'm just really reluctant to put it on this team. It doesn't necessarily solve all our problems as powerful attackers can still break through it with support. If we were going to add a bulky Pokemon I'd prefer it to be a bulky magnemite .
~Nozzle's Riolu
Nozzle didn't expand too much in his post, but Riolu is a fantastic choice for this team imo. It really gives us a nice check to other HO teams which would otherwise be slightly problematic. With copycat, it does a fantastic job of checking many glass cannons and also beats Scraggy meaning that changing Murkrow to scarf isn't necessary. It's difficult to say what Riolu can do for a team because it always finds itself in random situations that require quick thinking with copycat, but I'm confident it would perform well in this team.
~Corkscrew's Chinchou
Clearly the best choice ;) Just read my post if you want to see my reasoning.
~Dcae's Pawniard
I suppose Pawniard can work quite well with this team, patching up weak points against Lileep and Snover. I feel it would leave us far too weak to Magnemite and Tirtouga though who I believe to be the biggest threats right now.
~Lunatic Lie's Croagunk
Croagunk has some great synergy with this team and I've used it in conjunction with a Murkrow/Drifloon core before as it patches up weaknesses to Shell Smashers, Lileep and it checks Magnemite. It also checks the water types that beat Drilbur, and the fighting and grass types that can beat Tirtouga. Definitely a solid choice for this team, but I don't know if Mienfoo or Riolu would be better fighting type choices because of Riolu's ability to deal with a plethora of random things and Mienfoo's knock off support. Croagunk does have dry skin and poison typing though which sets it apart.
~Kingmitus's Timburr
Despite being my favourite LC mon to use, I just think the other fighting types offer more support for this team than Timburr. Croagunk checks Shell Smashers better and Mienfoo and Riolu give us more offensive momentum.
~Superpowerdude's Mienfoo
Another decent fighting type on the list, with Fake Out and Knock Off, Mienfoo would offer a lot for this team. U-turn will also help keep the momentum on our side of the field which is really nice.
As you can't vote for yourself my vote is really torn between Riolu, Croagunk and Mienfoo. I don't like Porygon on the team, Pawniard leaves us too weak to Mag and Timburr just doesn't fit the style of play. Again, Chinchou is nice but the team may struggle with Lileep so I'd bare that in mind if you're going to vote for it. I'm probably going to vote tomorrow after thinking it over some more, but one of those 3 fighting types is best in my opinion as the main threats at the moment are Lileep, Porygon, Magnemite, Tirtouga and Chinchou. EDIT: and Snover, blarajan.