Thanks boost... so the stock tahoe brackets will not fit for the dEnali (lol). Also, if the tahoe headlights will not fit this bumper, then will the denali headlights fit the rest of the tahoe grill and hood?
No, there are subtle differences in the grille, hood, headlamps, bumper, even fenders of any GMT 800 GMC Yukon from a GMT 800 Chevrolet Tahoe. If you changed one component, you would have to change the remaining components as well in order for the lines to match.
Although similar, if you would want to do this modification because you can find an inexpensive Yukon Denali bumper, the rest of the work that you would have to do to make to modification work would completely overwhelm that.
To illustrate what I am saying, look at a picture of a GMC Yukon and Chevrolet Tahoe and place them side by side. Where the hood of the Tahoe meets the grille, it is a straight line, but in the Yukon, the hood cuts up slightly at the corners to accomidate the slightly larger headlamps. Additionally, the grille of the Yukon dips slightly into the differently shaped bumper, where once again the Tahoe grille and bumper are straight across. Also, where the fenders meet the headlamps, the angle is much sharper on the Tahoe than on the Yukon. And finally, the air dam on the Tahoe is slightly wider than that on the Yukon (although the Denali bumper doesn't have an air dam, the remaining contrasts still hold true). There are probably additional differences as well, these are just the visually apparent ones.
Essentially, if you were do attempt this modification you would have to replace every body component from the windshield forward in order for it to look right. If you like the appearance of the painted bumper, I would simply recommend swapping your bumper and air dam out with that of a GMT 800 Chevrolet Tahoe Z71, which also has the round fog lamps that you said you liked. Hopefully this saves you from a major headache later on, take care!