It's worse than that, (he's dead) Jim
(sorry, couldn't resist

)
Not only is what you say about the (acoustic) sources themselves true, but their interaction with the room/surroundings also modifies their perceived output as well, further mismatching their timbre/tonal qualities. It would be indeed rare to have matching tone across the front stage without some eq, just from such interaction.
Like you, I would advise the OP that it's ok to "mismatch" models, but match the levels with the test tones in his receiver (which hopefully also has some eq capability), sit back, relax and enjoy.
Well, at least until it's time....to upgrade the mains

.
cheers,
AJ