Try to get a bike set-up where the handlebars are close to the same height as the saddle, or maybe an inch or two higher. If the handlebars are too high, so that you sit upright, you are more comfortable, but not very aerodynamic so your commute will be slower and harder. If the bars are too low, as a heavy fellow it will be hard to lean forward over your abdomen. If you lose some weight you can lower the bars a bit.

If your commute is all on pavement, I would recommend not getting any suspension as it adds weight to the bike and slightly adds effort.

I would recommend a firm saddle - squishy gel saddles seem more comfortable but they can cause more numbness in your male parts. If it has springs underneath, that is okay. (If you do start to notice some numbness as you ride, just pedal standing up for a minute or so).