Specifically, I’m having issues internalizing all of the different present possessory estates, present and future interests, and rules re: covenants/equitable servitudes in such a way that the facts (essay or MBE) trigger the rules. Other stuff like mortgages and landlord-tenant is fine.
Flushing out the material here may be helpful. I'm not an expert or Prof, so correct my statements as needed. So there are present possessory interests, which are of course different from future interests which may or may not vest (become possessory) down the road.
Fee Simple ("to A" or "to A and her heirs" or any language saying FSA) This is ALL of the land. It's basically the best thing you can get. Yeah you know this.
Fee Simple Determinable (To A for so long as, while, during, etc... So long as the status quo continues - if things stay the way they are now - the recipient continues to have possession. It's important to characterize this FSD properly, because if the status quo ceases to exist - title automatically reverts to the Grantor. This is called the possibility of reverter. If you have a FSD, the possibility of reverter is always paired with the FSD.
Fee Simple Subject to Condition Subsequent The language here are things like "but if X happens." If some event occurs in the future, the Grantor will obtain the power of termination (i.e. right of re-entry). The key here is that the right of re-entry must be exercised by the Grantor; it is NOT automatic like the possibility of reverter above. (This can make a difference in adverse possession cases, where it's important to determine who has title at what time.) Also be on the lookout for RAP problems with this type of conveyance, because the condition (for example: "if an Independent is ever elected as President, then to A's heirs") could be something that might not happen within 21 years of the conveyance.
Those are really the main possessory interests. An executory interest is one held by some 3rd party. For example, this is a FSD subject to executory interest: To A so long as A continues to do community service, but if A stops doing community service, then to B. You can see that B has an executory interest.
Future Interests...they can be sure to vest (indefeasible) or capable of being destroyed (defeasible).
Vested remainder: To A for life, then to B. B has a vested remainder in fee simple absolute. A will certainly die at some point, so B is sure to take!
Contingent remainder: To A, but if A dies before B, then to B. There's a possibility that B will never get anything, his future interest is contingent on surviving A.
Which other types of present/future interests do you want to discuss?