You should be absolutely fine. 1) New calendar year 2) You returned to country of domicile. If you are risk averse just get a Tourist Visa but I doubt you need it. Enjoy your Run
My last job was as a Director at a large Japanese company reporting to the C-Suite. Most of my previous experience was in British or USA companies. The culture was much different shall we say. :-)
To get a Non-B with WP you need to be employed by Thai Company. For O and WP is same, Thai company. The LTR is available if you earn enough and the company is large enough. That is a better option.