Let's see... Lon'qu's hairstyle makes me think of Luxray & there's the fact that Lon'qu & Luxray starts with a "L"...
Not sure if that matters to you, but Luxray is a good late game pokemon, as it can learn Discharge, which hits all enemies in the room.
& he'll also take 20% less damage from physical attacks.
You could be a Leafeon, which can attack & heal at once with Giga Drain & can put enemies to sleep with Grasswhistle.
(but keep in mind that the enemies of the later dungeon often has IQ skill that prevents sleep.)
Leafeon can learn Swords Dance & has some good physical attacks to use with it:
Quick Attack, Razor Leaf, Wide Slash, (If you want, I can get you a wonder mail password that'll get you the Wide Slash TM.) Dig
& Bullet Seed.
While Lon'qu the Luxray would cover your Flying weakness, you'd cover his Ground weakness.
I can think of other options, if you'd like me to.
EDITED IN:
Luxray's IQ skills will allow it to deal HUGE amounts of damage, but at the cost of defensive ability, which is counter-acted some because
of the Intimidate ability. (& also the Intimidator & Brick Tough IQ skills.)
He can get a IQ skill called Erractic Player, which causes type trumping to be more effective both ways, so turn it off in dungeons with Ground types
& turn it on in dungeons that has primaily Water &/or Flying types.
Try to get his IQ to 5.5 ASAP, because he'll be close to learning Extra Striker, which sometimes makes him attack with the same move
twice in one turn, at the cost of an additional PP.
Extra Striker will make Discharge especially good at clearing out Monster Houses.
Leafeon's IQ skills are more about utility, like allowing it to cross all terrians, get extra EXP, destroying traps instead of triggering
them when you step on them, sensing the general direction of the stairs, getting extra PP & occasionally not using any.
Also gets Gap Prober, which will allow you to use moves like Razor Leaf & Bullet Seed to help your allies fight by shooting though them
& damaging enemies only. (but turn it off if you're not controlling Leafeon, because AI pokemon with Gap Prober will try to attack though walls,
which isn't possible in most cases.)
There are other great IQ skill that these 2 can get, but this should be sufficent amout of info to help you decide what to do.
