1. You can, but you NEED to be aware of blackhead disease turkeys *can* catch. Proper parasite control can prevent it. Stock load and personal pasture conditions including weather can vary widely and may impact this.
2. Some will kill chickens, others may protect them. Not sure about human aggression. Are you looking at keeping hens or toms or both?
3. No medicated chick feed will NOT work for young turkeys. They may survive but they won't be thriving. They should get a 30% protein turkey starter until a certain age. They NEED more amino acids and such then chicks. A 28% protein game bird starter would be an OK feed.
4. I would NEVER recommend someone keep breeds that are meant to be processed at a young age. My friends heritage breed turkeys can fly, they killed one of her hens AND one of her chihuahuas! Once she eliminated the aggressors, the remaining turkey hens actually protect her chickens.
5. Reference #4. Yes, it's true that fast growing breeds can face leg problems. While killing and culling may seem the same to some... culling is done with purpose. You may need to cull any bird due to serious injury. Maybe consider getting a midget white instead of the BBW?
While my nutritional info is accurate, my turkey experience is very limited. Please consider my suggestions a good starting place but hopefully you will get answers from someone who actually raised the breed you're look into.
@R2elk are you able to share any insight here? Thank you!
Quick link to another thread discussing turkeys and chick feed..
https://www.backyardchickens.com/threads/can-turkeys-eat-chick-food.1299341/#post-21157246
ETA: I see ya beat me while I was posting!