It's a 50:50 match up. Oh, you're asking how to fight Lucas. It's similar to fighting Ness. His f-smash is the only smash that doesn't have a bad start up. If you're going to roll back onto the stage [from the edge], it'd be wise not to always do that since it allows him to use his u-smash and that attack has wide range on it. To deal with his PK Fire spam, just jump around it and dodge it. That should be simple enough. If he uses PK Thunder, you should be able to react to it on time so you can absorb it, even when you're off the stage.
If you get him into the air, I recommend you don't try and uair him as Lucas' dair goes through it. You can also use PK Thunder against him, but like Ness, chances are he'll just absorb it. Lucas' PK Thunder 2 isn't too much of a threat unless you get hit by the ending strike from it, so it's good to play it safe just in case. Any stage Ness is good on, Lucas is also good on. So your best bet it to probably take him to a stage that is neutral if possible. If you have any major issues against Lucas, what are they?