I don't think your new PCs would know Fahlias is a follower of Trandim, unless he wears Trandim's holy symbol openly....though his half-silver-dragon nature will be obvious and probably offensive/aggression-provoking to the lizardfolk....
Unfortunately, I don't think there's any reason for a Dracon Boyaris to be adventuring outside Paludosus, unless he were just on a mission in an enemy country to destroy something or someone there. I don't think there's any reason he could really be hanging out with a bunch of humans, their gnome, and their half-dragon traipsing about in the North and Middle lands doing random stuff.
The setting guide says to determine starting wealth by actual level, not ECL, though the DMG handles it otherwise. So your lizardman would start with the gold of a 13th-level character, 110,000 gp, by T13K rules. Also note that his actual level (13) would be what factors into his Leadership score and the maximum level of his cohort
Item creation costs would be used instead of market prices for any magic items your character may have crafted before joining the group, but note that that includes XP costs as well. Depending on how soon the new PC joins, I may or may not just start him at the minimum XP needed for ECL 14, but otherwise the XP costs would make him start a little ways short of that level.
Chariots and double chariots (two-person chariots) are in the Arms & Equipment Guide. If you're thinking of one for your new PC and his cohort, you'd need a double.
"Double Chariot: Large Vehicle, Handle Animal +2 (for controlling the vehicle, which gives +2 on the Handle Animal checks for that purpose), Speed: drawn (poor) (speed of the horses or whatever draws it along, with poor maneuverability), Overall HP 80 (hardness 5), Overall AC 4, Ram 4d6 (damage dealt if it rams into something at full speed), Face 10 ft. by 5 ft. (probably just a 10x10 ft. space in 3.5; it's roughly 10 feet long and 5 feet wide), Height 5 ft., Crew 1 (plus 1 passenger), Weight 600 lbs., Cost 400 gp
Occupants of a double chariot gain one-half cover (in 3.5 that's just cover I think) behind 2 inches of wood (hp 20, hardness 5). Two light warhorses harnessed abreast can pull the chariot at a speed of 60 feet. By swerving the chariot, the driver can have it follow behind either horse (this choice doesn't count as movement)."
Note that the cost of the horses is not factored into the chariot's cost (since different animals or different kinds of horses could be used, light warhorses are just the norm for a double chariot).