Don't sweat the mismatches. But, if at all possible, get internal cam levers. especially in front. There are two basic types of levers, those with external cams on either side of the QR head and a lever coming out the middle and the internal cam where all you see is a lever coming out the side. The cam action on the internals is far better, allowing for much more secure clamping. (Also only use QRs with steel skewers: the rod that runs through the axle. Steel, by its nature, has far better ability to hold tension when you limit the diameter - no choice there; it's gotta fit through your axle.)

Cheap steel Shimano QRs are excellent. There are plenty of other good, cheap choices but the Shimanos are common, very easy to find and sure fire. Oil the head through the hole for the lever and where the skewer enters every so often.