If in the future I'll ever need to replace my front wheel, I'll pick either a 700c or a 27" one, so the caliper should keep working just fine.. Is there something else I should consider?
If you pick the 27" wheel & tire in the future, then make sure you have room. That's going use up at least 8 more millimeters (≈5/16") clearance to whatever the closest point of interference is. Might be even less room if your current tire size is under 32 mm width
Not sure what I think about a 700C on the rear and a 27" on the front. I'd want same size wheels.
PS. You can put pics in the Gallery here on BF and just let us know they are there.