Yes, if you are interested in creating your own GHPython components on top of the Ladybug Tools software, you should consult the Ladybug Tools SDK docs here:
https://discourse.ladybug.tools/pub/ladybug-tools-core-sdk-documentation
There is also searchable documentation on all of the existing LBT components here:
https://discourse.ladybug.tools/pub/lbt-grasshopper-doc
Yes, you can create your own data collections from lists of values using the components under the Ladybug Analyze Data tab.