Can I observe in a salon in Bangkok on a tourist visa and what other visa options are available for me as the spouse of a Thai citizen?

I’m traveling to Bangkok soon with my husband and children who are all thai/British. I am British only and usually just fill the entry form in on the plane for a tourist holiday entry. I am a hairdresser and as we are having an extended trip I have the opportunity to do some observation in a well known salon in Bangkok. This would not be paid and I wouldn’t be doing any hairdressing, only observing to share expertise. Could this be deemed suitable for my tourist visa? Also am I able to apply for a different type of visa/dual passport etc as I am married to a Thai? We live in UK currently but may not always be the case. Thank you for reading!