Sodium ethanoate is the same as sodium acetate by the IUPAC nomenclature. The reaction of urea and Na2CO3 is, as you have already figured out, something else. Urea tends to pyrolise in HO-CN and NH3 in a reversible fashion. If the NH3 gas escapes you get the HOCN+urea product (biuret) or further on the HOCN+biuret product (isocyanuric acid). Other conditions can lead to melamine (2,4,6-triamino-1,3,5-triazine). But if you have Na2CO3 present at the start you only get NaOCN since the reactive HOCN acid gets neutralized imidiately to its heat stable sodium salt. Hope this clears the confusion.
Do you know how long the reaction would take, temperature, and also whether a lower concentration of HCl can be used?
I think most amides get hydrolysed faster with NaOH than HCl, but urea may be an exception, I don't know. You should bee able to notice the end of hydrolysis by the end of CO2 bubbles formation from the boiling stones if you lower the reflux bellow the boiling point for a moment. Usually this is a clear sign in reaction involving CO2 formation (like the Leuckart or decarboxylisations). If I dare making a guess I would say that 6h of reflux would do, but don't forget you need an excess of conc. HCl since it gets neutralised by the forming ammonia (at least a 20% excess). If you will use the 20% HCl put a somewhat larger excess and reflux for a longer time.