Need guidance from Texas or Southern gardeners ...

We have Bermuda in the front yard 1/2 acre And Kentucky Blue grass/ Fescue on the back 1/2 acre..
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Which goes down on the yard first ...The weed without the feed or the Fall fertilizer...Would you please name a product that weed and does not feed please...I have the fertilizer just can't figure out the name brand of a product that just de-weeds our yard...

Also its still gonna be 80 degrees in the afternoons for the next couple weeks...when is the temperature correct for the applications of both??

Thanks for your help.....