If you are serious about doing this correctly, you absolutely need to make sure that all the front speakers have the same or very , very similar drivers. IMO, all ear-level speakers should be the same as well. But that's a discussion for another day.
An example of why this is the case is simple. In a movie scene you have characters talking and moving around the soundstage, left to right, front to back etc. As the characters move, their voices should not change in any way. If you have mismatched speakers, you will hear tonal differences as the characters move across the front and/or to the back of the room. This can become quite distracting. I have heard this many times in client's homes and it's not subtle.