These are some great vids *subscribes to channel*, and I really like your use of the usmash. I would focus a little less on dairs and more on his other aerials, though. His fair/nair/bair all seem like they would make nice approaches if spaced properly, and if you whiff one, you've always got jabs, the dtilt, and maybe the down B(?) if it can be canceled fast enough to stop from being shield grabbed or hit by a <insert attack here> out of shield. If the aerial ends before you hit the ground due to hitting a shield, either do another aerial (does nair eat at shields? it might be a good one to try, particularly if it has low lag) or attempt a pk fire backland if there's time. The dsmash might also work to cover landings, if it comes out fast enough, as I know it hits multiple times, giving the possibility to shield stab.
For edgeguarding, instead of always chasing with either pk freeze or pk thunder, give pk fire a chance if they're in your jump's reach. In fact, give pk fire a try anytime your foe is knocked a distance away from you and slightly upward, and try to stay away from pk thunder, except when they're at higher percents. I haven't used lucas myself, yet, but from what I've seen pk thunder gets its best use when the foe is already near a boundary and about to die.
Specific vid examples:
http://www.youtube.com/watch?v=P0Rp-HM4OEQ
At :48, instead of pk thunder, try jumping and doing an aerial
1:02 is a good example of a time to try pk fire
After your pk fire at 1:32, would've been an almost perfect time to jump and follow up with another one; by the time you reach zelda, she's already out of tumbling, but you would've hit her before she landed if you had used pk fire again
1:37 would've been a good time to pk thunder, as she's far above you, is fairly close to the boundary of the stage, and is going outward; you won't reach her in time with anything else, but might've gotten her with a pk thunder, and hopefully led into multiple hits toward the boundary
At 2:31 you use pk thunder when zelda's only at 49%, and you end up only doing a little more damage before she lands, which you still wouldn't have been able to follow up on even if you had hit with the orb of it; instead, waiting for her to come closer to the ground and either using pk fire or an aerial such as uair or fair probably would've been more productive, and possibly lead to edgeguarding opportunities
I think you get the point. Like I've said, I don't have the game yet, but these are some ideas to try.
edit: I noticed you never used the snake for recovery, except for one time when you were really far away anyway, and it wouldn't reach. I don't know exactly what kind of range it has, but it seems you were using the pk thunder close to the edge several times unnecessarily.