The expressions are okay, but are not equivalent to each other due to shades of meaning. For example, I don't see "not good" and "lousy" as the same. "Keeping busy" and "I'm swamped" also have a slightly different degree of meaning. This applies to all the expressions listed. 

The how are you ones are a bit odd. A native speaker would understand what you're saying, but each one gives a certain impression of the speaker. "How's tricks" sounds like someone from the ghetto, and "Hows by you?" sounds like a country bumpkin. 

Different expressions are good to know, but you should check with a native speaker exactly what they mean before using them in your vocabulary. 

Also, expressions can be more prominent in one geographic area over another, so some of these may not be common to some English speakers but would be familiar to others depending on where they live. 

Expressions usage can also vary by the age of the speakers. 

Q: How are you? (I normally use this) = This is often used.

How's tricks? / How's it shakin'? / How's by you? - I have heard of the first one, used between people that know each other well. The other two I have never heard.

A: same as usual (I normally use this)  This is fine and often used.= I am getting by  - this is ok but usually used by someone who has experienced problems.

just muddling through / plugging along  -  the saying is "plodding on"   but not used a lot.

Fair to middling - this is often used but not really said to someone you don't know.

A: not good (I normally use this) = Lousy / Crummy I have heard Lousy more than Crummy and only between people who know each other well.

A: keeping busy (I normally use this) = Swamped / I'm snowed under / I have heard these often.

Been running around like a chicken with its head cut off. The phrase is "running round like a headless chicken"