Should these questions about creating a pen name be asked together or separately?

Question

I'm looking for a list of advices and factors to take into account when choosing a pen name, both out of curiosity and necessity.

The main points that interest me are the following :

• When should a pen name sound like a real name ?

• How to create a pen name fit for your writing genre/style ?

• How to be sure a pen name will stand the test of time ? (I usually get bored of my pseudonyms fast, use different ones for every website I sign-up to, and don't want this to happen if I choose a pen name)

Should these questions be asked separately or grouped in one general question ?

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Some explanation :

I'd like to share some of the short stories and scenes I wrote somewhere (blog or sharing website, I haven't chosen yet). The thing is that I don't want to use my real name.

There is nothing special about my first name but my last name is too uncommon. Putting it on the internet would create serious privacy problems since a Google search of it returns only stuff about my family and I. To give you an idea of how uncommon it is, I don't have any homonym.
Plus, it's too location-specific. It's from South-Western France and sounds a little "hillbilly-ish".

For Writing SE, I used the classic method "Name of your first pet + name of the place you grew up", which gave me Cerise + St Hilaire.

Answer 1

I think you might as well ask these questions separately, as they will need to be addressed separately anyway.

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Some quick advice right away (that you did not ask about): If you can, use your real first name. That will it make much easier for you when you visit conventions, do public readings, or appear on tv or radio, because you will automatically react to someone saying your real first name, while you may simply not "hear" someone address you with a name that you are not used to hearing from family and friends, and that may seem strange and will give away that you use a pseudonym.