There is no minimum income requirement. You can include 2 contracts. Show the agreement you have with the data annotation platform and highlight payments received via bank account/PayPal. No problem showing the 500k in a Thai account.
The children would be dependents via the main parent DTV. The soft power activities are culturally based such as Thai cooking. Muay Thai or via medical treatment. You should.check the main DTV group on FB, for tips on applying.