Is "invitation letter" from son living & working in China on talent visa o.k." for our application?

Hi, We don't want to purchase our tickets, etc. before we get our visa to go to China. This means we have to wait til it's three months before we travel so that ours doesn't expire. This will be a problem as we need to book our hotel, tour package etc. much sooner. What do we do? Also, will an "invitation letter" from my son who works and lives in China be acceptable for us to apply for it? He is on a talent type.

Thank you.