Most DTV requirements are Embassy dependant, so first choose where to apply from, and remember you have to stay there during the WHOLE visa processing time.
Not married = separate application, separate bankaccounts.
Doesn’t matter, neither you or any Embassy staff can edit the passport information, as you would know from both the Embassy website and the e-visa manual.
Do NOT buy a flight back to Thailand until you have the visa, since you don’t know how long the visa processing will take, especially if additional documents are asked for ( which resets the clock to zero) of an interview is requested.
Changeable tickets may be so much more expensive that it will cost to much
You could have started by reading any Thai Embassy and the e-visa websites thoroughly, including the manual in top right corner.
Then you would have know that all and any mistakes ind the passport informations, is immediate grounds for rejection, and only a new application ( and visafee ) can change that.
Now you have to find out who you are, and what your name is, corresponding with the info in the machine readable field at the bottom of the picturepage of the passport