You should also know that when buying and selling there is fee, typically 100 baht per baht weight on bars, some shops may lower if you buy bulk, some shops may be higher, ask their fee first. Same goes for jewelry but the fees are higher depending on the shop and craftsmanship of the jewelry, typically 1500-1800 baht per baht weight. It goes without saying that jewellery is not a good investment buy.
This is the website that sets gold prices in Thailand. Prices are set daily at approximately 9am and follow the market fluctuations. Price is set only once Saturday morning and that price is maintained until Monday morning.
You can apply for the DTV, after you get your Visa number then you can apply for your son, citing your visa number as the primary holder, pay the fee for the dependant, and provide a financial sponsorship letter and your funding information again.
There's no requirement that you need to have accommodation but it doesn't hurt to have a booking for a week or so while you look around for something.
You can bounce out at 180 days and come right back in 5 minutes.
If you're applying as some kind of remote worker or a freelancer you will probably need to justify it with bank statement showing pay slips, that kind of thing. You can provide all that in the beginning or you can wait for them to ask for it, if they do. You simply need to convince them that you are a genuine freelance worker and have a client history and possibly a portfolio.
Completely depends on which embassy you are applying at. Some want to see the funds there for 3 months, others don't care if it was just put in the day before.