This is just one small part of your question, but in The Unredeemed Captive, John Demos tells the story of a family from Deerfield, Massachusetts, who were victims of a Mohawk Indian raid and subsequently forced into captivity.

Though most of the family was eventually released, one daughter, Eunice, chose to stay with her captors, eventually marrying and completely integrating with her new family. Demos makes the argument that this was not entirely uncommon, and that the lifestyles of many indigenous peoples were superior to the hardscrabble existence of early colonial societies, leading some Europeans to voluntarily choose to join native communities or remain 'unredeemed' as Eunice did.

Also, please be careful with the word 'assimilation', it carries with it a lot of unpleasant connotations that historians try to avoid.

On this, can anyone tell me whether or not the French/Indian connection was a positive one? I've heard that the French intermarried in order to get hunting permits from the Indians but it slowly changed to a more abusive relationship between the 2 over time.

Do Native nations allying with Europeans to fight against other Natives count as "positive interaction"? Because there were plenty of instances of that.