Bought this beautiful house in Nova Scotia, in add. to above, is also dirt floor crawl space ranging in height from 12 ins to 4 feet. Project: maximizing heat retention and minimizing moisture. Crawl space has 1 vent which is always open and the walkway hatch which can be closed. My concerns: a)Exterior insulation of the rock wall foundation would be nigh on impossible due to de-stabilization issues and local factors. b)Insulation of the interior rock walls may lead to frost heave issues with the exterior side. c)Insulation of the 'tween floor joist spaces, may lead to rock wall foundation failure due to loss of heat from living space. d)Inability to have a true moisture barrier from the earth(despite 6 mil poly) due to uneven rock foundation attachment issues. e) yeah. yeah.....lots of issues LOL So, I guess I am asking if anyone out there has such a house, and what they have done to deal with them.

I have an older house (1906), though much younger than yours.  I would think the biggest bang for your buck would be to airseal the crawl space from the house, i.e. to prevent bulk cold air from crawl to enter the house.  My house had an uninsulated hunch space, and post and pier construction, basically open to outside.  I was amazed at how much air was moving up from below, the house was a big chimney.
As for moisture, high moisture levels could be a function of poor downspout control, and surface/sub surface flow that can be mitigated by regrading soil around the house and trenching in a french drain system.  I'd start by looking at water and moisture flows around the house, your crawl space has a roof after all.
I know nothing  about frost free slabs, but perhaps look at such designs for ideas on insulating the ground outside of your rock foundation.
Good luck, and kudos for buying such an old house.  They are worth preserving.

Agree with above advice.
Our home in Connecticut is circa 1895 with a shed over a crawlspace attached in which we put a bathroom. We insulated the underside of the floor using batt insulation with a vapor barrier on the cold side. No more cold floor in winter.
Our neighbor had a dirt cellar which, when she lined the floor with concrete, decreased moisture in house. We have several ledges which rise above our basement floor which had cement poured around the ledges. With a dehumidifier in the basement in summer, we have no more mold problems.
To keep the drystone basement walls dry, rain gutters are set to lead all water either to a dry well away from the house or into a cistern for use in dry spells. (we had about 1000 gals saved up when we lost power for a week to our well after a hurricane.) This system works so well, that even when basements around us flooded, the only leak we had was from a crack between the chimney and basement wall which needed recaulking.