Hello, we are building a 1300 sq.ft. vacation home, slab on grade, near Ottawa Ontario, Canada (draft floor plan attached). We plan to use it a lot when the weather is warm and twice a month during the winter.

For heating, I had considered propane-fueled hydronic radiant floor heating, and for cooling, a Mitsubishi Zuba, either ducted or mini split. 

Because the Zuba is designed for Canadian winters, capable of heating to -30C, and because there is an add-on component of electric heating for when temperatures drop too low, it seems like the perfect, singular solution for heating and cooling. That said, I plan to drop the hydronic floor heating altogether. As a consolation, and to have warm feet, I plan to install electric in-floor heating in both bathrooms.

My question is, should I go with the Zuba-Central (heat pump outside is connected to an air handler in the mechanical room, which is connected to central ductwork) or go with the Zuba-Multi (heat pump is connected to a device in the mechanical room, from which a variety of mini splits feed to various rooms)? 

https://www.mitsubishielectric.ca/en/hvac/professionals/zuba-family/Zuba-Multi

I would prefer the Zuba-Multi, because then I could avoid the ductwork. However, I am nervous to run these lines through the walls and ceiling, because I fear there may be potential for water damage, either from condensation or other. I would like to use either ceiling cassettes or ceiling-concealed units in both bedrooms, and one unit, either a wall-mounted or ceiling-concealed style for the main living space.

In my view, the Zuba-Central ductwork is safer, because the ducts won’t leak water in my walls and ceiling, but what I really want to know is if my fear of installing the Zuba-Multi lines in the ceiling and/or walls is justified? How risky is it to install these lines in a ceiling and/or wall?

Any info is greatly appreciated!

Thank you