Update on above: The American Standard Furnace in Option 2 above is 100,000 BTU 2 stage model AUH2C100A9V5.

I think you should forget about the American Standard dealer. His prices are high and he does not know how to properly size equipment.

The Trane dealer at least has a reasonable price and size. You want a Trane coil, no third party substitutes. Not sure if the thermostat is the best choice.

Here is a copy of the load calc showing 3.5 tons. I was told since there is no 2 stage 3.5 ton condenser I should go with the 4 ton. Is this correct? Is 95% AUH2C100A9V5 100k BTU correct furnace for this load calc? Is the 4 ton 4A7A7048 Gold 17 Air Conditioner (Platinum XM Air Conditioner) 2 stage the correct condenser? Should I downgrade to 3 ton? Or should I go with a single stage 3.5 ton?

I am a little skeptical of this calculation. The summer temperature is a little too high, and the winter is not low enough in my opinion.

Some of the numbers are strange. The heat gain from people is about the same as the walls. Do you have many windows facing the south? You have 1.5 tons of heat gain just from the windows. There is a big loss for the fireplace. I would have thought that would be covered in the infiltration number.

"Existing unit cooled and heated satisfactory (when it worked). Of note, both Family room and Foyer have 20 foot ceilings."

If this statement is true, then there is no need to increase the size of the furnace or AC. The Trane dealer sizing seems more realistic. Get a third quote if you want more data points.

I have some large windows, but they are west facing. Yes, the old unit (when it worked) cooled to 76 and heated to 71 but had to run continuously on the coldest/warmest days to get there. I am amazed at the difference in prices for similar equipment: $12,444 (American Standard) vs $7900 (Trane). Are there any major manufacturers that offer 3.5 ton two stage condensers? That would be a good place to call for my next quote.

Also, am I better off with a single stage 3.5 ton condenser versus an oversized 4 ton two stage?

Running continuously on the hottest and coldest is not necessarily a bad thing. In theory that is what would happen when you are at the indoor and outdoor temperature design conditions.

Two stage AC condensers are only available in whole ton sizes. I really like my 2-stage AC. It does a great job in humidity removal. I think in NJ you are better off with the larger 2-stage equipment. It would also depend on the low and high stage capacity of the unit compared to the load calculation.