Can we return 2 table themed arrays in function
The issue is you're passing elements that a render array would use, such as the "#rows", "#sticky", etc, but Form API will ignore them, because anything prefixed with a "#" will be treated as a property of the form element. 

Clive gives here (https://drupal.stackexchange.com/a/27269/28556) a very concise explanation and solution for that, which consists in creating your own theme function to render a particular element.

Additionally, I think you could, as well, use the existing theme('table', ...) function to render the table from that same function, but returning the results as direct markup instead.