I do understand your questions as some people have been brought up with very little opportunities and aspirations and never even considered a passport. I find civil servants in Thailand very helpful and as long as you find a passport office they will guide and help her.
There is a need to start discussing taxation if you intend to or will become a tax resident in this fiscal year (183 days of more physically present in Thailand 1st Jan - 31st Dec 2024). If not by default or plan to manage not to there is no need to worry about tax. Next step is how black and white the new changes are … or just grey.
Short term rental (less than a month) is illegal in Thailand and has always been but everybody including the condo owners are paying lip service to it even when installing the shiny threatening notices in their lobbies; we all know without short term rentals the already oversupllied condo market would collapse. Building even more condos is fuelled by short term demand (yet full legalisation would never be allowed by the hotel association lobby). My understanding of the status quo … all is a grey area, nothing black and white.