Maybe you could ask a friend (or whoever is sponsoring you to live in Thailand as a tourist for such a long time with no money in your bank) to put some money in your bank today so you can show a healthier balance.
Fly to a nearby country with a Thai embassy/consulate and buy a tourist visa (or whatever visa is appropriate for your reason for the long stay). On your return make sure you have 20k THB cash on hand (and proof of onward travel if coming in with a tourist visa).
Great business idea! Charge people for a guarantee of something that is completely out of your control, refund some of them who don't get lucky and keep the rest.
It depends more on what you want to do here than where you come from. There are one year visas available for studying, working and retiring, the latter two of which can be renewed every year forever, assuming you continue to meet the requirements. The other option is the Elite Card, which you can just buy, with visa durations from 5 years to 20 years.
Sell it to a car dealer (and give the money to the charity of your choice if you want). If you give it away, or dump it, the receiver will probably sell it anyway, and you wont have the paper work to protect you if it used for some crime.
make sense. the old rules were a waste of resources for the immigration officials to go to check people were working at the office location stated in their work permit. it's 2018 now, many jobs don't require people to work at the same office all day everyday, and many people have more than one job or business and/or do part-time volunteer work.
what you describe is considered work. the only type of investing not considered work is when you have no involvement in operations or management (for example you buy some shares in CP company)