Criminals wanted in 5e
How about this; everyone makes up a 1st level thief type, no multi-classing until after the characters have reached 3rd level with GM approval. Open multi-classing after characters have reached 5th level (w/o GM approval). The characters will begin as members of the same group (gang, clique, club, crew, etc. call it what you will) from a poor district in a larger city that I will create specifically for the campaign to run/begin in.
Characters will be poor, starting with only 30gp worth of gear and place where they can all hangout (room at a cheap inn, an abandoned warehouse, a spot on the docks, etc.), a dagger, and a bad attitude.
all stats start as 14, you can lower a stat to raise another on a 1 to 1 basis, but no stat can be lowered below and 8 and racial maximums are the limit to raising stats.
so, you could could lower a Wisdom of 14 down to 10 and four points to use to raise your Dexterity and Charisma to 16 for example.
If you are interested let me know.