Yes, disconnect the speaker, please.
Get on the output jack & measure volts dc with your meter.
I think you will find a high voltage which means the output stage is blown.
The readings that you took on the output transistors indicates one or all are shorted.
At this point it is best to remove them one at a time until the short clears.
Make sure you check the 0.33 ohm resistors for opens.
Do you have a 'diode test' feature on your meter?