When to use です
As an example, if I have a casual friend who is the same age as me and I wanted to ask him/her a question, would it be too formal to say:
おなまえは何ですか？　/　猫が好きですか？
or would it to be better to get rid of the です (which doesn't sound right to me)
おなまえは何か？ / 猫が好きか？
or
おなまえは何？ / 猫が好き？
(These don't at all sound right to me ^-^)

-

Also, should I refer to my friend (x) as:
1) x　さん / ちゃん
2) x　くん
3) x (First name) / (Second name)
4) Other?

Question

When to use です
As an example, if I have a casual friend who is the same age as me and I wanted to ask him/her a question, would it be too formal to say: 
おなまえは何ですか？　/　 猫が好きですか？
or would it to be better to get rid of the です (which doesn't sound right to me)
おなまえは何か？ /  猫が好きか？
or
おなまえは何？ /  猫が好き？
(These don't at all sound right to me ^-^)

-

Also, should I refer to my friend (x) as:
1) x　さん / ちゃん
2) x　くん
3) x (First name) / (Second name)
4) Other?

Answer

First, you need to get rid of お from なまえ to make it casual. 
And it sounds weird like you're asking with 何か? ( it's limited to be used in kind of formal or old style writings) 
You can just say なまえは何? or if you want it more natural, say なまえは?.
But we normally don't use a casual style when we first meet and introduce each other in my opinion.

Answer

Hello,

getting rid of the です and or the particle か does not make any sense in that context as per my understanding.
First sentence sounds ok. 
To keep being polite, better use さん than can and polite usage is to use after family name.
In general, it is better for foreigners to keep talking in polite language even though Japanese relatives may sometime answer using more familiar language.
Of course their are exception but when you are not sure, that the common rule to apply.

Answers · 3

Still haven’t found your answers?

Don’t miss out on the opportunity to learn a language from the comfort of your own home. Browse our selection of experienced language tutors and enroll in your first lesson now!