What it sounds like you want is a routine that is as simple yet effective as possible. I know all the info here can be overwhelming, and sometimes we just need someone who has been here a while to break it down. You've gotten excellent advice so far, and most of it boils down to making sure you infuse as many moisture-laden products as possible into your regimen, and use a protein or ceramide to ensure that the weakened chemical bonds in your hair from the relaxer stay as strong as possible.
***As the Elasta QP mango butter is a moisturizer (NOTE: I have never used this particular product), try using it everyday and following up with the oil to seal in the moisture. Since you noted that your hair is extremely dry, you may want to M&S twice a day (once in the morning and once before bed) until you notice an improvement in your hair's moisture levels.
***Also, add in a weekly moisturizing deep conditioning treatment after using the Garnier Fructis shampoo to restore the moisture the shampoo may zap from your strands. I believe Garnier makes a mask, but by no means do you have to stick with one line. You can try Silk Elements, which has been mentioned upthread, or you can try something like Lustrasilk Cholesterol (the shea butter kind). There are threads and threads on great DCs, you just have to look for them.
***If in a month's time you have still noticed little improvement in the moisture levels of your hair, you may want to try using the Fructis conditioner as a cowash conditioner midweek. I personally love cowashing, something I discovered when I joined LHCF as a transitioner back in 2008. It took my hair to a whole new level of healthy!
***As far as protein goes, try a leave-in that contains protein, such as Aphogee Green Tea + Keratin spray, or add in a protein DC, like Aphogee 2 Minute or ORS Replenishing Pak, when you notice your hair feeling mushy or an increase in breakage. If you go the DC route, once every other week should be fine, and make sure to still use that moisturizing DC afterwards!
Your regimen seems as if it has a solid base....you just need to fill in a few gaps. HHG!