First of all, I would question your logic explaing why triethyl orthoformate is supposedly more acidic than ethanol. Most carboxylic acids are more stable than most alcohols, but here we're dealing with a type of ester of a carboxylic acid. Totally different situation. I could not find the pKa of triethyl orthoformate from a google search but I doubt it's more acidic than ethanol. Somebody please correct me if they can find the pKa anywhere.
Also, there are more factors that effect acidity than just the one you named. You're correct that more acidic molecules have more stable conjugate bases, but there are many factors that effect the stability of a conjugate base.