Torres del Paine, Moreno Glacier and Fitz Roy ( Chalten) are located in the same area, so I think it is better to make it at the same time.

Usuahia and Bariloche or Esquel ( I myself prefer Esquel - Parque Los Alerces ) are at considerable distances so you have to fly preferably.

I don't know what about flights is Chile, but I imagine that you can go from Santiago to Natales ( you have to check with small companies, I checked Lan Chile and they are not going ).

>From Buenos Aires you can go to Usuahia ( several flights per day ). Also there is a new airport in El Calafate, and I know that there is flight that makes Buenos Aires, Bariloche, Calafate, Usuahia a couple of days per week ( company called Southern Winds).

I would go to Usuahia and then from there to Calafate or Natales ( either by plane or bus if don't mind travels).

What I remember when in Calafate, was that they offered tours to Torres del Paine ( by car may be 4-5 hours from there) and to Chalten ( Fitz Roy) in 3-4 hours.

Nothing is too crowded in Argentina &Chile, we are very few people and lot of territory, the difference is that Bariloche is more improved ( or spoiled) by the human hands. For example, roads inside parks are paved while in Calafate, Esquel and so on , only main roads are paved, and the rest are stone consolidated.

You can rent a car ( much more expensive for USA standards) or take a remise cabs ( like a taxi, but with a fixed established rate to different locations )

Very safe, never heard of any problems. People is a little basic, but very helpul at all times. Services are not very much in the area, but I guess they can repair anything by themselves. If you go by the normal roads , you can expect help from any other car, bus and so on.

People will probably speak in a basic English , but I am sure you will have no problems ( many foreigners in the area all the year ).

I think February and March are OK for the trip, you do not expect rain very often in Patagonia.

Hope it helps

Best regards Guillermo in Buenos Aires