No, not like Lucas & Ness actually. Marth is definitively better imo, as proper spacing can lead to higher damage and earlier kills. The only difference between the two is that Lucina doesn't have a tipper (dmg/kb equal along the whole blade as opposed to sweetspots & sourspots) and is marginally shorter. Lucy is easier to do well with tho imo.

You might wonder about my boy Roy. Unlike in Melee, he's Marth But Better. Some might argue otherwise, but to me he's a semi-clone like Lucas. I like to call him the result of a fusion between Marth and Ike. He's a lot faster and stronger, while also falling significantly faster. His sweetspot is instead at the base of the blade, meaning for optimal damage you need to basically punch them in the face. Most of his moves are generally the same (with the exception of what is basically Ike's dair and Roy's own neutral B) albeit with at least slightly different animations/properties. He plays differently and a lot of people consider him clearly superior to the other Weeb Emblem chars. Also worth noting is that a fully-charged neutral b (about 5 secs of charging) from him is either an instant shield break or KO. Like you literally can not survive a full charge unless you defend perfectly. Good thing it takes two years to charge up.

As for Lucas, he is a semi-clone of Ness, while Luce is a full clone. Lucas obvs is very similar to Ness, particularly in his specials, but they all have different properties. PK Fire is a single hit and fires straight forward in midair, so it's not as good of a punish/move in general as Ness's. I personally use it for a careful approach or doing a weird B-reverse thing with it to retreat. PK Freeze is basically Flash but a lot faster and a lot a weaker. It obviously freezes them and you can rack on some damage as they are frozen. PK Magnet is the same except for it's in front of him and has a hitbox. PK Thunder does multiple hits and goes further when launched but does a lot less damage / knockback.

Most of his other moves are pretty much different in some way with the exception of fsmash, uair, fair, dtilt, and jab. Even then they're at least slightly different. Also worth mentioning is that Lucas has a tether grab, which has its own pros and cons, but the primary difference besides range/speed is that he has access to zair, which is him throwing out his little tether in mid-air. It can't grab as you can imagine but it's a quick tool for spacing and poking that most fighters don't have.

Well anyway that was much more than I needed to write but there you go