The Minolta 7 was a pro level body, not as fast shutter speed as the 9, not as well constructed, but it as the last film body it will work with all Minolta A Mount, Konica Minolta A mount and Sony A mount, gear driven and micro motor lens. Not Sony E mount. The 9 was top of the line Pro level camera, stainless steel body, weather sealed, top shutter speed of 1/12000 of a second 1/350 flash syn. The 5 was the entry level body. I would stay away from the 7SI and 9 SI, they were a generation earlier and used a set of command cards for advanced features, like action, landscape, multiple exposure. If you decide on a 7 or 9, buy from a dealer with a return policy or warranty, like KEH.
I know that you are interested in Minolta, which is my main 35mm system. I pulled out my Pentax PZ 30, a step above the entry level PZ10. I used mine for street shooting for several years, even took off the plastic shell and painted it olive green, used with 50 1.7 KA manual focus lens and AF lens. I had forgotten how many features it has, only lacks mirror lock up. Very quite. Light weight, Pentax makes really good lens.