I think these should be as clear as possible so here are my suggestions:
##Menu Items
- Add > Mesh > Cube is very easy to type, it gets the point across and provides a logical flow of operations as the brackets hint that each item flows into the other as opposed to listing and separating items with pipes. Italicizing these also separates it from the rest of the content and that is enough.
- For menu items that have entries in the manual, these can be linked in if you deem it necessary.
Example: Add > Mesh > Cube.
##Shortcuts
- There should only be one word on each button so either of these can be used interchangeably.
Example: CtrlShiftM and Ctrl + Shift + M are perfectly fine as long as they are chained together in the correct order.
##Links
- The default and normal use of links is fine so this is ok.
- For links to the api, it is ok to use backticks (as these are code).
Example:bpy.context.region_data
##Images
- There is already an entire post dedicated to ways images can be optimized. See http://meta.blender.stackexchange.com/q/197/12
##Other
- I agree that we should use back-ticks sparingly and only for code, filenames, extensions, parameters/arguments and links to the api for functions. Don't use this for mere highlighting purposes.
I will further update this answer as you update your question.