Hi,
Item 19:
The question is: Where do you measure the output voltage. If it is at Rl, then the output voltage is zero.
Item 23:
With the emitter resistor the base current is not zero. But when the emitter is open, then i expect no base current, too.
Without current there will be no voltage drop in the base driving circuit (source, resistor, capacitor). I'd agree the base AC voltage increases.
Item24:
With the collector connected properly, the current in the emitter is the base current plus the collector current. This causes a voltage drop (AC) in the emitter resistor.
Now without the collector current there is only base current through the emitter resistor. The current is much lower than before, and therefore the voltage at the emitter is lower than before. Because the ACbase voltage is about the same as the AC emitter voltage...I again agree, that the AC basevoltage will decrease.
(...low batteries, sorry)
Klaus