So you want to apply in 1 year. Do your research when you want to apply then your information will be current. You need to choose the best option given your situation but Muay Thai would be easy for you. You can apply for DTV anytime why you want to wait.
Applicants don't stick to the criteria as asked by the embassy. They try to put more documents because their portfolio is not high standard. This leads embassy to believe they are not what they say they are. So ask more docs or reject. Follow the rules it's a 5 year visa not for fun do visa exempt if you don't have solid application
Border bounce for DTV is every 180 days = 6 months or just before. I fly out and back stay 2 or 3 nights small holiday . Go where you want but you can take your cat if you drive your car and cross. It's what is closer or more convenient for you. Maybe others have done crossing in one day
You need to leave and apply for a non b in Thai embassy. You work needs to give you the paperwork you apply non b 3 months when you come back your employer the applies for 9 month extension in Thailand local immagration followed by your work permit at labour dept
No income required for soft power. Dont give documents that are not required it will be your downfall. Check in the search bar for the embassy you want to apply. Then find soft power successful and follow what they do. Don't listen to many people here make you confuse
immagration are not being difficult they are being very nice and asking legitimate questions in relation to your visa. It's just people who are not legitimate are concerned they may not have what is asked so they get nervous. Like you said genuine people have no issue