Thank you all (Patrick, Trav & DW) for the input on my situation. I understand there's a lot of options in leather repair/care and hearing all the different options possible is quite intriguing.
To be more specific with my goal, the bag has to look uniform in color, as it's a handmade gift. Luckily I do have a lot of leather samples I can attempt these treatments on first before touching the bag.
The options so far:
1. Gently rub with Reno'mat / apply similar color cream
2. Condition / burnish leather (would avoid using water in this case as the leather wasn't been conditioned for months)
3. Condition / spray dye leather
If it's interesting for thread, I can show my attempts using all the methods above on semi dyed pieces of leather. This whole bag situation has been an incredible learning experience in just how mind-numbingly difficult leather care/repair can be.
Don't dye the leather. Leave it as is, or else resort to coloring cream for better effect and ease of removal in the longer run.