In the first picture, you seem to missing a charge from bottom right to bottom left, and I think that OH is probably the better leaving group, to be honest. If you treat an ordinary ester, say ethyl acetate, with ethanol, I'm not sure any reaction really occurs (or if it does, the starting material is the same as the product). If you use methanol, you will get transesterification.
Have you learnt about acetal protection of ketones and aldehydes?
Your second scheme looks very unlikely - EtO2CCH- as a leaving group, and hydride shifts?