Confidence is a uncountable noun which does not require a definite article before it. Attitude is a countable noun and should have an article, in this case the indefinite article, in front of it (or in this case before the adjective preceding it). Finally, the last word in your sentence is ungrammatical as it currently stands. It would be better to replace 'ease' with 'with ease' or 'easily'. So your sentence might then become:
In the game of life, it is confidence and a positive attitude that helps children sail through with ease.
Bread and butter is a standard interlinked phrase in English, but it is usually used in the figurative sense of a person's means of living that allows them to provide food and shelter for them and their family. That is not to say that it cannot be used literally, as in your case, but I would have thought that bread and water would be a better description of 'the minimum requirement of every human to survive', with 'bread' meaning some kind of nutritious 'food'. In this case the two (ie food and water) may be considered as inseparable; a person cannot survive for too long without both. However, even in this case it would not be wrong to say:
Bread and butter are the minimum requirements of every human to survive.
I would not consider Confidence and a positive attitude to be an inseparable phrase, although the two are sometimes used together. Whereas it is difficult to argue that 'Bread and butter is the minimum requirement of every human to survive', there are many other options that could be put forth as being things a child needs to be able to sail through the game of life with ease, e.g. good self-esteem, wealthy parents, a good education, a happy home life, positive role-models, etc.
If, in an article or book, an argument had been presented for the proposition that 'confidence and a positive attitude' are the two most important aspects leading to success in the game of life, and had created a mindset in which these two aspects can be thought of as inseparable, I would have no problems with the sentence:
In the game of life, it is confidence and a positive attitude that helps children sail through with ease.
In the absence of such an argument, I would personally prefer to see:
In the game of life, it is confidence and a positive attitude that help children sail through with ease.