There are now and again things that I come up with about Leander that are probably unlikely to come up in a game session but that I think are likely to help develop his character, so I'm planning on collecting some of these thoughts here in hopes of remembering them and giving added depth to the character.
Leander's backstory mentions that he was a frequent RTS and FPS player. In specific, the games that Leander played as a youth would include StarCraft I, Warcraft I three III, CounterStrike, Medal of Honor, Command and Conquer 1 through 3, Total Annihilation, Civilization I through III, Doom 1 and 2, GoldenEye, the Marathon series, HalfLife and the Tomb Raider series. As an adult, I picture him disdaining slightly of Call of Duty and Halo, but enjoying games such as Portal 1 and 2, StarCraft II, Left4Dead 1 and 2, the HalfLife sequels, Bioshock, Dead Space, and FarCry. He theoretically has both a Steam ID and Battlenet ID (or more recently a Battletag) which would be Leadast, a portmanteau-ing parts of Leander and Adrastos, and pronounced in a way that sounds somewhat like "Lead us."
Leander is a competent driver, but probably doesn't actually drive frequently. Much of his mercenary work has been in situations in which having a vehicle is either a luxury or a significant added danger, and therefore he's moved on foot much more often. He has, however, occasionally employed both jeeps and motorcycles as mounted cavalry in certain offensive and defensive scenarios.
Leander, as has been noted both in game and during character creation, is fluent in American Sign Language. Originally, Leander began learning it while wooing the daughter of one of his employers, but when she broke off their relationship (thanks to her father discovering it), Leander continued the pursuit as a way to add additional non-verbal communication to his combat skills. He frequently teaches at least a few key words to those he's leading and has likely done so with at least some of the soldiers and Scions he's worked with on Olympus. I picture Elene as having occasionally given Leander lessons entirely in sign language, probably having shocked him with the knowledge that she was fluent the first time she did so.