what do you think about having multiple blogs in one blogger account but each are talking about the same thing (titles and contents are spinned) ? will that raise a red flag?

i dont think so.

you should be ok. just make sure you don't have a ton of blogs on one Blogger account. of course, Blogger won't tell you the exact number, but I keep it at no more than 10 blogs per account. this saves me from getting my blogs banned.