Finally, I build form on 1 model extends Model and operate using class yii\db\Command in controller before validate select and after validate update or insert depands on count row select result.
This sounds like you need to use a ViewModel: a model that inherits yii\base\Model and which includes properties for both database models. When you submit the single form, the ViewModel class copies the entire post data into itself and then on save(), it puts the correct data into the correct type of database model and saves them both.
As for your second question, it is possible to have multiple submit buttons in a form but if you use jQuery, you cannot usually tell from $_POST which was clicked (because submit is routed via jQuery). There is a whole discussion here which suggests some Javascript tricks like saving the value into a hidden field onclick(): http://stackoverflow.com/questions/12850041/how-can-i-detect-which-submit-button-was-pressed