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Yes, you can safely remove the brown foliage. The draft of cool air could have led to this leaf browning and the fact that you moved it to another location should definitely help. However, there could be several other reasons for this and it's often difficult to pinpoint the precise cause. Brown leaves can be a sign of scorching, meaning that your plant is getting too much light. If this is not the case, look towards watering. Brown spots can also be due to a lack of watering. Fungus can be a cause as well, but this is more prevalent in overly moist plants.

Here is an article on caring for rubber tree plants that you may find helpful: https://www.gardeningknowhow.com/houseplants/rubber-tree/how-to-care-for-a-rubber-tree-plant.htm

They should not cause damage to the pipes or buildings around it as long as they are getting adequate water and have plenty of room for the roots. Trees only go after pipes if they are not getting enough water and only damage foundations if their roots have nowhere else to go.

As far as being damaging to the plants, they will not be from below in terms of roots, but if they are very large and larger than the other plants, they could be shading the other plants and possibly using all the water in the area. The light is easily fixed with some pruning of the rubber trees to let more light through their canopy to the plants below. If they are sucking up all the water, increased watering will help with this as well as pruning, which will reduce the amount of water they need.

You will need to determine if it is still alive. If any part is still alive, it should grow back. This article will help you:
https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm

If the stems are thin, it means that it is not getting enough light. I would move it to a better lit window or add a supplemental light, such as a fluorescent light, nearby. That will improve the stem strength.

These little pests like damp soil, so to get rid of it, I would recommend letting the soil dry out a bit more between waterings. As I am not sure if they are centipedes (not harmful) or millipedes (harmful), I would recommend that you treat the soil with neem oil. If it is millipedes, the neem oil will help to stop them.

Here is an article that you may find helpful: https://www.gardeningknowhow.com/houseplants/rubber-tree/rubber-tree-plant-leaves-falling-off.htm