70,000 btu furnace for 700 sq ft condo sounds NUTS.
Rheem's 80s have the solid front so usually will prove the quietest. The RGPE with 2 stage thermostat or the matching communicating control would be a nice system.
The Lennox and Armstrong furnaces are similar, single stage with conventional motor. York too, it's a low end builder model. They aren't in the same league as the CVA or RPGE.