Dead Discussion but I'll post anyway; I have a bit of insight on the Falco MU if anyone is willing to listen, lol.
For starters, and as others have said, powershielding lasers will only get DK so far against falco. It's a gimmicky approach at best, and Falco's moves/overall pressure game cycle much faster than your defensive options can cope. The number one way to combat Falco's pressure is, of course, to not allow it to commence, and that all starts in neutral.
What Falco wants is to force DK into desperation maneuvers like dash or shield grab and up+b oos, and every single Falco player by this point understands how simple and effective it is to shut down the great ape with almost disrespectfully negligent tactics. The first thing you have to realize is that the only time Falco should be getting close to you is when it is on your terms.
What I mean specifically is that there is time in between each laser, and if there will be almost zero overlap between a laser and subsequent attack (laser grab, laser shine, etc.), you've already failed, and you have to prepare to be attacked. Punish the startup of laser against aggressive Falcos -- visualize hitting the gun out of his hands as if you are some kind of karate master in a cliche action movie, while Falco's a quick-drawing stock villain. If he's making an approach, there will certainly be a period of time where an immediate nair or bair oos will be enough to do this. Consider it a sort of reality check; most Falcos are used to big targets reacting defensively and rolling away or something like that. But this is only after you've given up in neutral.
Falco's laser is more or less a giant compensation for his slow movement speed and lack of standard forward approach options. His dair can be scrary, but it's spacing is horrible and its hitbox, unlike Fox's dair, becomes inactive after it hits you/your shield. This means that if Falco wants to respond aggressively to your approach, he has to bair or utilt, which he cannot do if he's facing you.
This brings me to my next point: DK absolutely needs to threaten Falco's space. If I need to get one point across here, it's that in this MU, quantity beats quality, hands down. Stop hanging everything on that one dreamy, juicy punish. Get him in his shield and threaten him with spacing that he can't contest. Don't even worry about getting grabs at first -- threaten to push him offstage and put him into an edgeguard situation rather than trying to get a ton of uairs into a punch or w/e. Use down + b if he likes to stay grounded, and if you're spaced properly, he can't roll back without being hit by the second round of floor slaps. Speaking of rolls, watch out for them. Falco either has to take a hit or two in these pressure situations, risk jumping out, or he must roll behind you. After a minute of this, then grabs will be free.
Also be aware that cargo uthrow on most nautral stages, under platforms, will result in an automatic tech chase, so never try to uair immediately. I've seen high level DKs fail at this. Just wait out tech in place and uair autocancel (no fastfall), because not teching is the same punish, and tech roll can be punished on reaction. After that, utilt takes care of the rest.
Hope this helps.