That should be one great mango tree once all those grafts start giving you mango. Im also thinking of doing something similar with a Glenn mango tree i have. Good luck!
Some poo poo cocktail trees but if you understand some wood will be dominant and some recessive regarding vigor and can control or prune accordingly, should be no problem.
If you have acreage then I would do single varieties but since I'm growing in a greenhouse, real estate is valuable. With the latest grafts my collection includes LZ, ST, Pineapple Pleasure, Fruit Punch, Cotton Candy, Juicy Peach and yet to push is Zinc (parent of seedlings like ST and others), and Cushman, popular in Hawaii. I left one branch of Mallika alone.