I just went through this process. I booked through agoda. I recommend booking directly from the hotel.
You will need a letter from the hotel that says you have, Airport transfer, 2 tests and 7 days accommodation. After I booked through Agoda I couldn't get anybody from the hotel to respond to my messages. Eventually I had a Thaifriend contact them and it became more complicated.
I recommend contacting the hotel before you book Make sure you can find a hotel where people will be responsive. Book the hotel, get the letter, etc.
My hotel eventually made all the arrangements for me, PCR tests and airport transfer.
I think what you suggest is doable. I dont really know, I have not tried. I am 45 without a wife so I haven't tried dependancy visa, but I think you can.
Thailand is great I love it here and I think you will too.
Also this groups is for every kinda of question related to Thailand and you are in the right place.
A) Book directly with the hotel. Get a contact and talk to them. They will need to provide a letter saying you have paid for transportation, tests, and accommodation. Originally I booked through agoda and it was a real pain to get the letter.
B) I had to submit my Thaipass twice. Maybe I goofed on the passport number, but when I checked status it said there was no record so I had to do it a second time. Once you've completed the process, check the status so you know they have record of it.
years ago I set-up Paypal both the US and Thai version. I found it wasn't worth the hassle. Now I have a local bank account and my US bank account. I transfer money between as needed.