Hello,
By using Search in Key Commands under Preferences, I could not see the result of the following features
Will they be included in future version of Dorico?
These are all currently accessed via popovers. For example, for a two-stroke tremolo, select the adjacent notes, Shift-R, 22, Enter.
I know the team is always adding more key commands as options, but there’s always a question of development time compared to pay off. And since these are already accessible through popovers, the motivation might be small. I can’t say.
You could always program a macro if it’s a frequent-enough operation.
This is my number one complaint about Dorico ATM. Everything in the sidebars should be key-bindable. They don’t need DEFAULTS but they should be keybindable. This is one of the few things the new Sibelius UI got right.
I’d say a two-stroke multinote tremolo would be obtained with 22 in the shift-R popover, Dan 
The first number is the number of strokes, the second “2” is there to make a multinote tremolo.
Have you tried mapping a shortcut for anything in the Zymbols panel?!
How would you make key bindings for new entries you create in the sidebars (e.g. playing techniques, custom key signatures, new master pages, etc)?
Fat thumbs!