yes it is. Im not sure how long it takes to get these days, I was on one a few years ago and things have probably changed since then. Someone here will be able to help you with info on it
Theres no reason to think that someone that has money in a thai account has been working there. Many people with Thai accounts transfer money in from abroad
yes, you dont need to say anything about your condo. You get an automatic visa exemption stamp of 30 days when returning to Thailand so if you are coming back for less than 30 days you dont have to do or say anything. Just give your passport to immigration when you return to Thailand and they will stamp you in for 30 days
You dont need to worry your visa validity will expire when you are away and you can just reenter on a 30 day visa exempt stamp if you are only going to be back here until your condo lease is up. You dont need to do anything