Lucas main here.
PK Freeze, as much of a pain as it is, can be easily avoided given you know how, and I'll tell ya how! Shield, air dodge, maybe even spot dodge if you time it perfectly. Just remember that PK Freeze always follows a particular pattern; it covers a long distance horizontally, but does not travel very far vertically. It's not impossible to avoid at all and once you get the hang of avoiding it, it will become almost second nature to you.
For PK Fire, use your jumps as an advantage. Remember, shielding and spot dodging are not the only defense tools you can use on the ground. Lucas' PK Fire comes out quicker than Ness' so if you want to avoid it, you need to react just as fast. Luckily, jumping is very quick and can get you away from the PK Fire untouched. Always stay on your toes and try to recognize any patterns. For example, some Lucas' (including myself) try to strategically use PK Fire in certain situations. If you can recognize this pattern, you can easily punish the Lucas. Also note that Lucas' are more prone to use PK Fire if you get in their face, because that is Lucas' best tool to keep you away.
For PK Thunder, just remember that Lucas is completely vulnerable when using this attack. Get out of the lightning's way as best you can, and then go in for the punish. When Lucas uses PK Thunder on the ground, there's a lot of end lag so he won't be able to immediately follow up with an attack, and that's your golden opportunity to strike. If Lucas is using PK Thunder to edge guard you, use Ridley's wings to your advantage and try to your best to stay out of the lightning's way. I personally haven't mastered this when I play against a Lucas, but it's the best advice I can give you.
Lucas' Up Smash is another particularly easy move to avoid. Tips? DO NOT TRY TO ATTACK LUCAS WHEN HE'S DIRECTLY BELOW YOU. If you are getting back onto the stage by jumping from the ledge, there's a chance he'll catch you with the Up Smash. So try rolling onto the stage. It all depends on where Lucas is standing in relation to the ledge. But I cannot stress that enough, DO NOT TRY TO ATTACK LUCAS WHEN HE'S DIRECTLY BELOW YOU unless you're super fast. It's also important to know that when Lucas uses his Up Smash and misses, he's left vulnerable for a few seconds so it's can easy punish for you.
Ah, the neutral air. One of my favorite tools in Lucas' moveset. I'm going to be honest, I'm not 100% sure how to counter this one. If the Lucas you're fighting is very aggressive, keep him away from you because he will more often than not try to spam the neutral air. Don't try to attack Lucas from the air too much when he's on the ground because he can easily jump up and cancel your attack with his neutral air just because it's so fast.
I hope that helps in some ways.
