replacing stolen rear wheel. compatability question
The 7-speed cassette standard has been functionally discontinued for new wheels.  Most new wheels come in 8-10 or 8-11 speed compatibility.  Since the 7-speed cassette bodies were shorter, you can install a 7-speed cassette on a 8-speed body using a 4mm spacer behind the cassette.  Alternatively, as you said, you can use the 7 shifter on an 8 cassette, you'll just have to tune out one of the gears with the limiters and cable tension.