Playing vs a Luigi is quite a strange matchup indeed (at least when I've played luigis). I would call it even for default because luigi has a difficult time landing and swordfighter's aerials are certainly capable of edgeguarding or slight juggling. But if you get trapped in a luigi string, there isn't much you can do about it. Back air won't save you all the time. Vs Doc it's also an even matchup because as long as you avoid bad ledgeguard situations, swordfighters have a fighting chance. Doc's grab game isn't as intricate as mario's so you generally have better chances of living a grab combo. He has powerful kill moves, but swordfighter's weight can help with that.
With a custom, I think these become favorable matchups because 1, I find that a small swordfighter can escape luigi strings better. 2, He can juggle better, and that's a huge detriment to luigi's because of the air speed. But don't get too crazy, he has that nair. 3, you can equip a reflector and instigate gimps better yourself vs luigi and especially Doc. And with the right playstyle (I have had the best success with a bait and punish playstyle with both default and custom vs these two) you can secure a solid victory.