php evaluation, token insert, tinymce, shared library..

1 - see https://github.com/backdrop-contrib/php - you'll need to install manually; it is not available in the project browser due to the risks associated with enabling it.

2 - there is Token Filter

3 - no module currently

4 - create a module with the library in. Make the other modules depend on it. See https://github.com/backdrop-contrib/fullcalendar_lib as an example of a library module where two other modules use that library.

5 - that module has not been ported.  Depending what you want to do, it may be possible to achieve the same result another way.

Hey aubergine. I can answer some of these :)

1.We don't have a PHP filter in BAckdrop for form textarea fields - it's dangerous. See discussion here.  Devel provides a PHP Execute block which allows the admin to type code for debugging purposes (it provides a textarea similar to Devel's Execute PHP page).

2. The token trees provided by core has the ability to insert tokens into fields (only if set up to do that - see $variables['click_insert'] in theme_token_tree()  . It's not as fancy and complete as D7 token_insert contrib module, though. But that could be ported?

3. Currently there is no port ot tinymce that I know of. Interested in porting it? you can disable ckeditor. 

4. There is an explanation of the current approach to libraries here. In a nutshell: the module Libraries API exists in Backdrop (as contrib) but has been deprecated. The current approach is to wrap the library in your module, which of course, makes it difficult to use by another module. One recent solution has been to write "library wrapping" modules, and then, if your module needs that library, make it depend on that wrapping module.

 5. Entityform has not been ported (yet). Interested? Webforms fills the gap (though I know from personal experience that it can be a lot harder to work with - case in point: creating Views with submissions!)

I hope this helps.