Yep, most of the code is exactly the same.
This has already been addressed. 
If I understand you correctly, this is indeed how it works. Although from you description I am not sure what your end-goal is. Is the abbreviation gonna link to a separate dedicated post? In that case, use the auto-linkify theme. If you just want explanatory text when hoovering over the abbreviation (i.e. <abbr> tag, use this theme. You can also combine them.
This is not clear, can you explain exactly how you think it will work? If the “ballon” is gonna be a link leading to your post that I guess yes it will count.
Overall, I’d recommend simply to install the theme and try it out 
You’ll quickly see hot it works.