Module development and code questions

Hi,

I've been bumping my head on something that seems a very basic implementation in Drupal 7.60. Basically I want to collect values in a form and when the form is submitted redirect to external URL with parameters based on collected form values AND present a clean new form after the submit. My real life example will call an external servlet to generate a pdf and open in new window. 

How to check bad behavior module works ?  Way to test bad behavior

I'm going to attempt a simple family tree module in drupal 8.   This will be my first drupal 8 module so I'm looking for some rough guidance.     

This is the layout.   Each person has their own node with their mother and father as fields.    When I click on the family tree tab, it will show a family tree, query the mother and father fields and grab the mother and father for each of those going back 3 generations.    Simple right lol? 

I'm in the process of developing a Drupal module that I would maybe sell as a premium module.

I'm not too knowledgable about licenses and DRM, so these are my questions - under what license should I place my premium Drupal 8 module?

And the second question is how to technically protect the module against unlicensed use and unlicensed modification, unlicensed distribution?
What is technically possible, what is allowed by the license?

I need your help with composerize module. I don't know how to use this module. I am searching in drupal.org but i don't find anything.

Hi!

Is there a project for translation file creating (.yml)? Like potx.

Or I need make manually the .yml lang file?

for example:

# mymodule.hu.yml:
"Original English text": "Translated text"

Or can I convert my .po to yml? The translation-toolkit does not work (in Linux distros).