In my studies of EA, I have seen really nothing detailed on the ascendant, midheaven, etc. Do those 4 points play a significant role in EA?
A good way to conceive of this is the ascendant is the cusp of the first house. Thus its going to be the gateway into new experience, and in that life area the person will have a very 1st house-Aries-Mars-like orientation. Similarly, the MC is the gateway into the 10th house, and the person is going to have a 10th House Saturn/Capricorn orientation to whatever sign/planets may be on the MC.
A core EA principle is the House is always the deepest energy, the bottom-line level. The sign on the house represents what that bottom-line energy is going to be filtered through. Learning the range of possible ways that Aries energy filtered through, say Virgo, on the cusp can actualize. You always start with Pluto, the Soul, by house and sign. Then the nodes and their rulers. These 3 represent the evolutionary signature. When you have a grasp on that, then you interpret Aries (1st house) energy filtered through Virgo. To consider, WHY did this Soul choose Virgo rising in this life?
The gist is, you can't pick out one or three chart elements and analyze them independently of the totality of the chart. Everything goes back to the archetypes of the 12 signs and can be seen as expressions of them in various forms. And the underlying evolutionary signature, starting with Pluto, is the foundation on which everything else in the chart is based.
Further, the 4 angles are the natural gateways to the 4 quadrants of the chart. Thus they are cardinal in nature, initiating action and change. These are the natural conjunction, square, and opposition points in the chart. Passing through them can be stressful, because they require release from the known, into what is presently unknown. So they are like evolutionary mile markers. If you look at the material about the phases, the natural archetypes of those key aspects, you will see much about what those 4 angles represent. Conjunction (Asc), waxing square (IC), opposition (Desc), waning square (MC), back to conjunction. They also correlate in Earth physical reality, with the beginning of each of the 4 seasons of the solar year.