To answer your first question, yes, this is the quar who created ponku sauce. To answer your second question, yes, this is the Maender whose restaurant is the by-word for luxury. And to answer the third question, yes, they're the same quar.
Chaput Ponku, famous caterer to the royalty, exponent of Gwyntish cuisine, author of The Compleat Gywntish Cauldron Book, and the creator of decadent ponku sauce could readily have excused himself from military service. Various reasons are given for his enrolling in the ranks of the 3rd King's Rhyflers, ranging from an impassioned plea from the noble mother of a young is-Caerten (and subject of an unrequited love), to adventurous war-stories told by his Vice-Chaput Schulaen after closings, to rank boredom with high society of Coftyr, to a deeply personal hatred of food served by the existing victuals system of the Crymuster. All seem plausible.
The 3rd now seats both the enlisted and officers in the same hall, although the officers still take their meal in a separate partition within. The food of the mess is legendary. When the weekly menu is posted, quar swap favors to ensure that they will not be on duty eating duty rations when their favorite supper is served. The enterprising Ponku has supplemented his provided supplies and the larders of the officers with a network of local farmers, paying them with "gratuities" he extracts from the officers. He has reorganized the catrawd's victualler staff into a brigade de cuisine reporting directly to him.