These are Melee Combat feats so Lancer can pick them up as bonus feats, though nothing about them specifically requires melee... (as an aside, I still think Lancer should have gotten Basic Combat instead of Melee, but that's a different issue).
Mounted Combat Basics
You are at home riding into combat atop a mighty steed.
Prerequisites: Ride (Riding Mounts, Flying Mounts, or Swimming Mounts focus).
Benefit: When mounted, you use the higher of you or your mount's Initiative modifiers instead of the lower. Also, you gain a stance:
Deadly Momentum (Stance): You may only assume this stance while mounted, and automatically lose it if you dismount. Attacks you make with weapons with the cavalry quality get a +2 insight bonus damage. In a round in which you move more than 10ft before attacking, this bonus increases to +4.
Mounted Combat Mastery
You've ridden into battle more often than walked.
Prerequisites: Mounted Combat Basics
Benefit: When mounted, you use the higher of you or your mount's Defense instead of the lower. Also, you gain a trick:
Wave of Destruction (Trample Trick): You gain a free attack against any one character in or adjacent to your path. You may use this trick a number of times per combat equal to the number of Ride skill focuses you have.
Mounted Combat Supremacy
You are one with your mount.
Prerequisites: Mounted Combat Mastery
Benefit: When mounted, you use the higher of you or your mount's Saving Throw modifiers instead of the lower. Also, you gain a Trick:
Rolling Thunder (Trample Trick): Each opponent after the first only receives +1 to defense instead of +2. Also, the DC to avoid becoming sprawled increases by 5.
These might be a little on the high power side, not sure. I don't see people on mounts very often in my group, my players seem to think it's more effective to dismount once you're in range and let your mount get a whole separate set of actions...
Anyhow, from the Q&A thread over in FC discussion:
Unseat (Polearm trick, forte): With a hit on a mounted character, the rider becomes sprawled in an unoccupied square adjacent to his mount (your choice). This attack only does half damage (round up).
Need to build a feat tree, think that'd be the trick of the second feat in the tree, the first giving a 'set to receive charge' type stance, though wording it in such a way so as to not be redundant with Polearm Mastery might be a bit tough. Important to note, as a polearm trick, anyone with Spear Mastery could use it with a spear.