BF is a good option too, if you are in a plataform, and Marth is below you, and tries a usmash, you can hit him easily with a dsmash. The usmash may fail because its hitbox
Never go BF against a Marth, you'll get ***** like hell if your opponent really knows what he's doing...
Seriously, Marth is uber **** on Battlefield, his stupid sword goes through all of those platforms, hitting you while he is safe and Marth's platform game is great in general. Also, the stage is much too small for Lucas to effecively stay out of Marth's range and set up some mindgames. The edge is pretty much the only thing holding Marth back here...
Norfair is a great counterpick, as Lucas easily outmaneuvers Marth there (partly because of his Rope Snake) and the basic shape of the stage makes recovering somewhat harder for Marth.
Rainbow Cruise works as well if it is allowed, because Marth's jumps are way lower than yours, he falls faster and his up-b is easily punishable if he misses a ledge. Just stay away and spam PK Fire. When you see an opportunity, go for an easy gimp kill (and believe me, there are tons of possibilities)
If for some reason you find a tournament that has it counter-pickable, Port Town also works nicely (no ledges). You can PKT2 (and Zap Jump) through the whole stage as well, just remember to Lag Cancel by finishing it close above the ground. Don't forget that Marth is really light as well, so if you practice avoiding the cars you will have an additional advantage as Marth dies at ridiculously low percentages when hit by them. Zap Jumping and PSI Magnet aerial stall might help, but always remember that you waste your second jump that way and also take into account the lag from PSI Magnet. Magnet Pull-mindgames often help in avoiding his attempts to punish you, tho, so it really is a decent option.
So, I would say ban BF, strike YS (you should do that anyway lol), CP either Norfair or Rainbow Cruise. Brinstar is not the best choice IMO, it is inferior to both stages that I've mentioned above. Port Town would be nice, but it s usually banned.
Just talking about the remaining neutral stages: FD can be seriously considered here, which is really unusual for the "standard"-Lucas, because of it's size - go spam PK Fire and make use of that ftilt to hopefully punish some messed-up approaches. Also, go for PKT gimps, they are the most effective here.
Smashville is a tad better IMO because sliding dsmashes are always fun and the moving platform helps in outspacing Marth, who is almost entirely reliant on his spacing. That platform also is at autoland-height for you, a treat that isn't granted to that stupid swordsmaster. Lastly, you can sometimes recover onto this platform for unpredictability's sake, while Marth will not do so (too high above the stage and stupid lag because it has no ledge).
Lylat really isn't that great because it is rather small and Marth's sword still is stupid as hell with platforms... The tilting stage might screw up his recovery, tho, just don't count on that if you are facing a decent player.
Delfino, should it be neutral, is quite nice because of that PKT2-through-stage stuff, but Port Town would be better and a good Marth will easily avoid your attempts to do so.
Hm... After thinking about all of that for a while, I also thought about Pokémon Stadium 2. It actually is quite fun: the main part has only two platforms, which is acceptable, and the transformations mostly support Lucas. Rock Transformation is great for Craq-Walk mindgames with the hill (ftilt rocks!), sliding dsmashes and similar stuff. The hill also makes PKT stalling a viable option. Ice is nice because of sliding everything. dsmash, ridiculously long sliding JC usmashes, ftilts, utilts, whatever you like. Your smashes are great if you slide them, at least Lucas profits more than Marthyboy does. Electric transformation also allows for sliding stuff (especially dsmash) and ledge-cancelled usmash (IIRC). And last but not least, PKT is **** if you get your opponent in the air while the stage is in it's air transformation.
So yeah, hope you got some ideas out of that and use the legal stages to their fullest potential.
Wario analysis probably coming up tomorrow...
. The grab release is not a huge problem for me, but if it is a problem for you, go to Norfair. BF is a good option too, if you are in a plataform, and Marth is below you, and tries a usmash, you can hit him easily with a dsmash. The usmash may fail because its hitbox
