Here's a savegame for the last two multiplayer achievements:
- True Commitment: Multiplayer level 60 attained.
- Shopaholic: Purchased all upgrades and characters in multiplayer.

It took me around 30hs to earn that much xp so hope I'll save you some time.

Important note made by another user: If you plan to do other multiplayer achievements, replace the file after you finish them , because if you try to do them with this save file, they will not trigger, as this save already has them flagged as complete, so you won't get the achievement credit.


P.S.: The link of the save is on the description of the video.