Thomas Imondi faces up to 9 years in prison, will have to register as an arson offender.
Sheriff's office says he hit another with a handgun, was then stabbed.
Bond set at $10,000.
Three men approached the teen and his friends before the attack occurred.
Bond set at $100,000 for Jackie Carter III, 28.
Victims are expected to survive.
Investigators are working to identify the remains.
The blaze occurred in the 2400 block of Caledonia Street.
Blaze broke out in 1700 block of Lagrange Street.
A GoFundMe account has been set up to help pay for funeral expenses for Kristoffer Staler, 38.