Sizing and Installation become even more important on Geothermal. It adds a water side component similar somewhat to a boiler. Whereas a air source heat pump uses a fan on the condenser, which is preconfigured from the mfg., a geothermal needs a properly install ground loop, with adequate capacity (lenght of loops & proper backfill), then the circulation pumps much be sized and installed correctly. North Dakota is a fairly balanced climate, it's both very hot mid summer and very cold in winter (actually one of the most extreme climates in the US, next to parts of Alaska), so you'll have less of a compromise than you might for example have in Michigan, Canda, etc. where summers are more mild.
I wanted to provide an update and thank all that replied.
I've decided to go with Option 1 - Lennox SLP98 and XP17. I feel very comfortable with the Lennox dealer. They were definitely the most responsive and helpful and I've heard good things about them.
I was able to get quotes from Trane, York & Lennox. Interestingly enough, two of the companies that I contacted for quotes (including the one that has serviced this furnace for years), haven't gotten back to me yet.
I looked into geothermal but didn't think it was worth the money for our situation. Based on the operating cost comparison I received, the payback time would have been at least 20 years based on current electric and propane prices.