Re: mix-matched tires
First I changed my rear tires to a different brand from the fronts as the fronts were OK - NO PROBLEMS.
When the rears needed replacing again the fronts did too, so when I changed all 4 I did not go with the same make front & rear - NO PROBLEMS.
I've had no problems and I've pushed the car in the dry and the wet.
I do have approximately the same compund front and rear.
Obviously don't mix radials & cross-ply.