Buddhist pine (while tolerant of significantly more shade than most other conifers) cannot be grown inside conveniently or successfully. This applies to all temperate trees (deciduous and conifers). Tropical and subtropical species can be brought indoors when outdoor temperatures start going below 16°C in the fall but should be brought back out again in the spring to be healthy. If indoors is your only option, in order to get the healthiest ficus you can, I recommend you diy a small enclosure for your ficus using a 10/20/30 gallon(whatever comfortably fits the tree) aquarium with glass lid and a good Led or T5ho fluorescent fixture. This would allow you to control the humidity and ensure that it gets proper lighting. Oxygen can be pumped into the tank via a small air pump. To maintain the correct temperate you can use an under tank heater with a thermostat. The light and heat can be set on a day/ night cycle. High humidity and optimal lights levels (and of course correct soil and fertilization) are how proffessionals are able to grow such healthy beautiful ficus with trailing aerial roots that remind us of the rainforest. They usually do it in a controlled greenhouse but this is the closest second I have found. I know this was not what you asked for, however you can use or discard this advice as you see fit. To answer you question the closest tropical conifer, you could maintain as a house plant during the colder months but should still be brought outside for the warmer ones, would be a Norfolk Pine. They are not ideal bonsai material (although some still make the attempt) however are commonly available as houseplants.
