- Kill two Snipers
- Stun five enemies
From your perch, look down and in front of you, taking note of the rope that runs all the way to the Sniper nest to the southwest, as well as where the rope branches off behind the two large bushes. Go for the sniper first, then backtrack to take the rope that runs in front of the nest and further on.
Start off by taking a leap of faith and landing in the hay cart, then climbing out and ascending the nearby pole. From there, run along the rope to the Sniper nest, climbing in and taking him out with a hidden blade kill. Jump back on the rope, following it back to where it splits off, then along that route until it ends.
Climb down from the pole and make your way through the crowd and to the west. It's a few feet from your current location that you'll find another pole you can climb. Do so, then sneak along the rope until you spot the Sniper, taking him out with a Phantom Blade headshot. Move a few more feet until you run out of rope, then climb down to the ground level.
To the northeast, you'll be able to spot two guards standing near a carriage, then two more further on that patrol nearby. If you can't see them, pop into your Eagle Vision to see what we're talking about. When the coast is clear, sneak around the left side of the carriage, opposite from the two stationary guards, then approach the back of the structure they are guarding to trigger a cut scene.
Defend Elise - Follow Elise
This is where you can complete your second challenge, assuming you have Stun Bombs purchased and equipped. We didn't, but you can easily pick these up prior to the start of the memory, or return for another play through like we'll have to.
To survive the memory, however, defend Elise from all the Extremists, dropping Stun Bombs (if you have them) to disorient five enemies. When Elise starts to run, you run. When she stops to fight, you defend her. That's all you do. If she's running, you don't stop to fight. After a few minutes of some standard melee battles, the memory will be complete.