In Isaiah 30:6, a young donkey signifies knowledges of particulars. (Arcana Coelestia 2781)

In Genesis 49:11, this signifies the natural truth of the external spiritual church, also rational truth of the internal spiritual church. (Arcana Coelestia 2781[5])

In Matthew 21:5, the Lord's riding on a colt or foal of a donkey signifies the natural and rational made subordinate. (Arcana Coelestia 2781[8])

A "house" is essentially a container -- for a person, a family, several families or even a large group with shared interests (think of the term "houses of worship.") In the Bible, a "house" is also a container, but for spiritual things rather than natural things. In various uses a "house" can represent part of the mind, the whole mind, a whole person or even a church. The other nuance to the word "house" is that it is generally used in regards to our affections and desires rather than our thoughts and principles. This makes sense; we tend to engage our thoughts and rationality when we are out in the world doing our work, but when we are inside our houses we are driven most by love for our families and the desire to be good to those we love. So "house" tends to represent the things we want and care about -- which are ultimately the things that define us.