Welcome!!!
I didn't transition, but I know that you have to baby the area where the relaxed hair and natural hair meet. You might want to try a protective style so that it won't get too much friction (two strand twists, braids, etc.)
As for co-washing... In the summer I want to co-wash all the time! Right now it is 99 degrees in NYC, and wet hair is my natural cooling system

It's not practical, but the heat has fried my brain.
But, what works for me may not work for you. I would vary how often you co-wash to see what your hair needs. One of the exciting things about your hair is how individual it is. Like fingerprints.
I don't use grease, but it may work for you. Experiment (safely) with your hair. I have had all kinds of concoctions stuck in my hair (banana glue), and after more than four years my current routine involves not much more than conditioner.
I'm hope I was some what helpful. Please keep posting about your progress!