Tower Knight wasn't really all that hard. If you attacked his ankles and made him fall over he was a joke. You only had to make him fall twice and he was dead. Plus with all the walkways and whatnot to hide in it wasn't hard to take a moment and heal or whatever else. You weren't on edge the whole time. And level five in Demon's Souls wasn't as bad as you make it out to be. Sure the water was poison, but the things that healed you were very easy to get and you could carry a crapton of them around - plus you didn't get poisoned constantly. Not to mention the bosses in that level were absolute pushovers. I beat all of them on my first try.
I think difficulty is based on perception though, so while I may think something is hard you might not and vice versa. It also depends a lot on what type of character you've made.
Londo is below the Firelink Bonfire. Where the lady in the cage is - there's a set of stairs on the edge of the cliff. Go down those and then go down the elevator. Be warned though - you need these consumable hands to be able to go there. If you don't have them, you CANNOT hurt the enemies. They can hurt you, sure, but you can't hurt them.
It is handy, though, because there's a mage/blacksmith in a cage there and there's no enemies between you and he. it's also worth it just to go and get another Fire Keeper Soul. Once you get out onto the water, it's on the first body you see. Beware though, a bunch of ghosts pop up when you grab it. You'll likely be killed.
The assassin guy I set free, though I don't think he is one now, is in the chapel. The upstairs of the chapel is kind of shaped like a U so just go upstairs and go to the left as soon as you are in the room with all the Hollows. Then go up the stairs [there is another rapier Knight] and break through the boarded up door. Up at the top of the stairs is a guy in a cell. Provided you picked up the mystery key after the boar, you can set him free.
I thought he would be an enemy, but I don't think he is now. He's now at Firelink across from the lady in the cage. He gave me some kind of coin for letting him out. Pretty sure it's a special covenant coin or something else like that. Still, the way he talks... he's not just a guy living in this world. He's a killer.
One part robot, three parts fellow.

