It is important to notice that the neutral alcohol oxygen serves as the nucleophile. There is never any alkoxide in this reaction. This pattern, neutral nucleophile attacks first, then the proton is removed, is very common for neutral nucleophiles and must be followed. This is a practical and useful method for making esters, but it does make the strong acid HCl, which is often troublesome. A more practical variation is to add a weak base such as pyridine to react with the HCl and neutralize it.
Acyl chlorides are the most reactive carboxylic acid derivatives.
The electronegative chlorine atom pulls electrons toward it in the C-Cl bond, which makes the carbonyl carbon more electrophilic. This makes nucleophilic attack easier. Also, the Cl - is an excellent leaving group, so that step is also fast. Because of their reactivity, acyl chlorides are easily converted into esters and amides and are thus valuable synthetic intermediates. Such proton transfers are very common in acid catalyzed reactions.