Towing a mini on a MBZ Sprinter FR Sunseeker

[Angels18]

Hello, I am new to the forum and a novice on the rv world. I have a 2017 FR Sunseeker 2400S MBZ Sprinter. I am setting up my 2019 mini cooper 4 door manual transmission as my toad. I already installed the Blue ox BX1312 baseplate. I haven’t installed the BX8848 wiring kit yet. I opted for the Blue Ox BX4370 towbar and BX88206 coiled cable, both being shipped now.

I was thinking of getting the roadmaster dual hitch receiver with a 6 inch drop. Dual hitch, so I can put my bicycle rack at the back and carry 2 bikes. The question who have experience with this is... Is it a good idea to put the bicycle rack along with the toad at the rear? Would this set-up cause damage to the toad or bicycles when turning? Also, if you’re familiar with my gear, would a 6 inch drop be okay or 8 inch or 10? I know I can measure it but I live on the hills and I would have to drive both vehicles down the hill on a flat surface to find a true level spot. I am hoping that I wouldn’t have to buy the rise/drop adapter and finding out that the next size would work much better.

Another question is the wiring kit to the mini cooper. Do you have any suggestions or recommendations that someone can pass along, to make it installation less troublesome?

Regarding the supplementary brake system, I was thinking of the invisibrake or the patriot. Which one would be best for the mini?

If anyone has a mini cooper toad, can you share your list of ‘checks’ when towing. That will help me on not ruining both vehicles. If these specific questions were already answered, please direct me to the thread. Thank you for the help and response. I appreciate this forum and all the comments/suggestions that may come.