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You can use dopdf which is a free program to make the PDF. It allows you to embed the fonts before you upload your document. I know it works with MS Word, not sure what you are using at the moment.

Normally I just use Word's Save As a PDF, and it has the option to embed fonts, but then again, there's the option to embed fonts in to a docx also. I cannot vouch for either because I always use Garamond, but I have seen the options offered.

Whenever I have used different typefaces in my Lulu books, they have been automatically embedded when I convert the file to PDF format. I have never given a thought about which ones might or might not be allowed by Lulu but there has never been any issues.

The difference between many fonts is not always immediately apparent, 

http://wavian.com/font-list.html

https://www.fonts.com/content/learning/fontology/level-1/type-anatomy/type-classifications

so if you want to use them in an obvious manner you need to use fonts that are very different. But don't forget that they have to be readable also.

I have used mixed typefaces in many Lulu books (including some pretty exotic ones that are not on the list) with no problem.