I am not the heat pump expert but I will give you my opinion on some of your questions.

Most people on this forum view Goodman as a second tier brand. The prices for the equipment is generally cheaper and is preferred brand of low cost installers. The prices you have received for the Goodman quotes seem high.

Trane is a well respected equipment especially in the area of heat pumps. However installation is very important. You should not just concentrate on a brand and ignore the capability of the contractor.

I think some of your model numbers are incorrect. Check them again. You want the model number of every piece of equipment . This includes the heat pump, coil, and air handler. The quote is not complete without the correct model numbers.

I am not a fan of humidifiers or electrostatic filters. I agree they become expensive maintenance items. If you want good humidity control in the summer then I suggest getting a 2-stage heat pump. Low humidity in the winter usually is caused by outside air infiltration. Houses built on slabs tend to be drier than those built with basements and crawl spaces. If you think your house is tight, then there are some good humidifiers on the market which can work well if properly installed.

I suggest getting a 4 inch media filter instead of an electrostatic filter. A MERV 8 fitler is fine, but you could move up to a MERV 10 if you think it helps your asthma.

Trane XL15i or XR15 with best matching var speed air handler and HW VP IAQ thermostat that has dehumidify on demand feature.

I would add a pleated filter media cabinet and a whole house humidifier.

I would want the staged 7/12 KW heat strip.

I consider the pricing you have received on Goodman or Amana to be on
high side.

I would want a new heat pump system that has electronic demand defrost to reduce/eliminate unnecessary, nuisance, and expensive defrost calls. Trane has this feature, Goodman/Amana does not.

Many of the problems related to humidifiers and electronic filter cabinets are due to homeowners' failure to understand and perform regular PM.

IMO

Thanks for info and I thought the Goodman quote was high and had to ask them for the model numbers as it wasn't included in original quote. I now have the 3rd quote which I am currently leaning to as it is from a neighbor's company who was recommended by my original builder who is an energy expert.

Rheem RPQL036JEZ 16.5 SEER 2 stage heat pump with variable speed blower and communicating controls RPL037JEZ, Aprilaire 2210 air filtration, touch screen multistage thermostat, 10 year extended warranty including labor for $7246.

Nothing wrong with Rheem. Ask them to include a whole house humidifier.

What suze heat strip?

What mdl air handler?

BTW, Rheem has EDD feature which you need.

IMO

Do you even know if your house is dry? Try getting the humidity measured. I'm sure Depot or Lowes sells something. You may find out you don't really need it.

My house is in NJ. Recently had the attic sealed and the doors and windows are decent. My humidity has been hovering around 39-40 this winter, which I think is ok in the winter. no humidifier. Getting the house sealed might be better use of the same $ because it will save you money on utilities as well as improve comfort. Or, do both the humidifier and the sealing.

We had an energy audit 2 years ago and he said it was one of the tightest houses he had done. We used a sealed drywall approach when we built (http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/files/bscinfo_401_airtight_drywall_approach.pdf). In June I have to turn on the system because it is too humid more than for the cooling. My eyes are dry (Rated 3 out of normal 10) and I had to have plugs in eye ducts to help, so in winter the dryer air is a problem for me. Probably wouldn't bother most people. Probably continuing with a room humidifier may be the best approach as I am also very allergic to mold. I would hate to have it in my vent system.

If you want humidity control in the summer, do like TD suggests. Get a variable speed blower and a thermostat that does Dehumidify On Demand.

The Trane X15 is a single stage heat pump, but matched with a variable speed blower you will get decent humidity control.

If you look around for other bids, American Standard is Trane's sister company. Their models are usually a bit less pricy.

The large filter media cabinet is a must for you. You could pursue the electrostatic filter if you know what you're getting in to, as TD stated. A whole-house humidifier should not be a problem to install.

As to usage costs, I suspect any new unit with 15 SEER or higher should reduce your electrical costs by (maybe) 20%. (Going from 20yr old 8 SEER to 15SEER.)