I think the visa itself is more than 1500

Yes and if only known short time near impossible

Family connections , property owned , financials , letter of invite declaring you’ll cover all her costs and reason for trip , also your bank statements showing you can pay for medical etc , letter from her work stating she has job to return to . You’ll need copies of family ID . Photos together with date stamp . As much info as you can supply .

I went through agent 30k baht . You can do yourself much cheaper . Embassy doesn’t do they outsource . I forget the name of the place in Bangkok but embassy website would have . Also you will need to use their recommended photo place in Bangkok as they are very particular about photos . They say not to do plane bookings but we did and showed return booking and health insurance

Yes the process has tightened up . Probably trying to stamp out illegal workers . The 1 year reset is your 12 month entry not a calendar year . Remember we are privileged visitors and as guests we need to respect our hosts . Unfortunately many guests have abused this by bad behaviour or not obeying Thai law . This is now making life difficult for those doing the right thing .