What is the message you are trying to convey?

determinants to get happiness.....or ..determinations that get ( obtener ) ( consequir ) happiness or ... " things that achieve happiness "

You could also say "but I don't they play a major role IN determining a person's happiness. You could say but I don't think they determine our happiness. Or I don't think their influence or presence determines our overall happiness.

I don't think 'determining' makes sense in this sentence. It does not sound right. If I understand the meaning of the sentence correctly I would use 'needed' or 'required.' I would also suggest using a word like 'achieve' or 'gain' instead of 'get.' To 'get' happiness does not sound natural. It is more common to say that you would 'achieve' or 'gain' happiness. Colours affect our lives but I don't think they are (required or needed) to (achieve or gain) happiness.