For Hooked, you can solo-host an Obstacle course and type "/endgame" in chat to get it instantly.
Outsourcing can be done with with as few as 3 players. The player going for the achievement should host a 2 minute match of FFA. The host needs to get two assists while the two other players each get one kill. All three players will be have a tied score, so the win should go to the host by default.
Hold Still and Sharpshooter can be done on the map Train with the shooter and target standing on opposite ends of the track.
For Heavy Weapons Guy try to shoot one bullet at a time since the minigun has a massive amount of recoil.
Kill three players without dying to get a bounty. Kill a player that has a bounty to claim a bounty.
The 100 wins can be done solo in a private lobby. Create a FFA lobby with a 2 minute duration. The wins can be fully idled after starting the server, but it's quicker to actively farm wins by immediately typing "/endgame" in chat after the match starts (press Enter to open the chat box).
Deck Playable