Oh, oh -- I accidentally left out the word "have" and still got the sentence correct! Have I been wrong all along thinking that "have" or "has" needs to be in all of these sentences? I thought you would need the preterite of the verb if you wrote, "I reduced the list to six".
A, yes, pronounce the a. It means "to" in this sentence. However you'd probably be understood if you didn't. I'm not a native speaker, but in my experience, it's just like some phrases in English, where it runs together so much that some people learn to skip it, especially people without formal language education.