Where is the Charging enhancement from? We'll need to look at it specific rules to see how it interacts with things. If it was a critical hit then it would not, but a non-critical weapon multiplier like using a lance to charge is a bit of a different matter.
I guess I wasn't specific enough with my wording: Do not add stuff that only multiplies Power Attack damage to stuff that only multiplies total weapon damage. Combat Brute will not add on to the weapon multipliers because it's not a weapon multiplier: It's a Power Attack multiplier. Same thing for Leap Attack. Leap Attack and Combat Brute are not
weapon multipliers. They are
Power Attack multipliers. They don't combine the same way and thus need to be calculated separately.
Biggest thing first: The
lance has the wording "A lance deals double damage when used from the back of a charging mount." If you're going to use Leap From the Saddle, it doesn't look like you'll be getting the bonus damage from the lance or
Spirited Charge since you're no longer on the mount.
So unless you actually can be treated as being mounted while using Leap From the Saddle to trigger
Battle Jump then you pretty much need to stop right there because the trick you're trying to do isn't supported by the rules.
If you
can tweak the rules such that you're still treated as being mounted while benefiting from Leap From the Saddle and Battle Jump, then read on.
Looking further through your equipment, you've got the Riding Boots' effect wrong. They only function to improve a Lance's
critical multiplier to x4, which means you have to crit. The exact wording is:
"In addition, if
the wearer has the Spirited Charge feat, any charge attacks
she makes while mounted and wielding a lance deal ×4
damage on a critical hit, instead of the normal ×3."
In short, it's not going to do what you want it to. I assume you'll be keeping the boots on since they're generally understood to grant Ride-by Attack and a bonus to Ride checks, so if you want to see what a crit would look like with this setup I can provide the math.
Along those lines, note that the DMG2 version of Riding Boots has the Ride bonus as an untyped +4. The Magic Item Compendium version, however, has them as a +5 competence. The bonus to Ride checks provided by Halfling Outrider is also a competence bonus, so only the best one of those would apply. Usually the rule is the most recent printing of an item or spell, etc, is the one that should be used, and the MiC version is the most recent. Check with your DM to see which version of the boots you'll be using.
Now that I know exactly how you plan to do the charge, I have to tell you that
Leap Attack won't trigger. LA requires you to move 10 feet horizontally as part of a jump action, and then land in a square that threatens an opponent you wish to attack. I see no way you'll be meeting the jump or 10 foot move requirement since you're not even making a jump check to move much less moving 10 feet horizontally with a jump since you're dismounting from a medium creature and landing in an adjacent square to it. The first diagonal is treated as a 5 foot move, so a diagonal dismount won't work either. The only jump check you're entitled to make is part of
Battle Jump, and that's simply to lower the damage you take from falling. I recommend the Landing armor enhancement from MiC page 12 to counter any falling damage of 60 feet or less.
Combat Brute's Momentum Swing maneuver is going to be interesting to trigger. If you're triggering Battle Jump the first round via dismounting, that means your mount is usually at least 10 feet in the air since you have to drop from a height of at least 5 feet above your opponent. Your use of
Snatch won't work because one of the prerequisites is being Huge or larger, which your wyrmling is not. Unless you can ignore the prerequisites of course, which you haven't noted either way. You've noted that your mount has perfect maneuverability, which is a bit surprising given that gold wyrmlings normally have poor. But, if it is truly prefect then you might have the option of dismounting and making the attack, then your mount can move down low enough for you to mount it again and then it can fly up high enough to perform another Battle Jump and thus you can get another charge in the next round.
Another thing to note is the interaction between
Combat Brute and
Leap Attack. It's a bit ambiguous whether Combat Brute merely modifies Power Attack damage (so that it still counts as a normal use of Power Attack) or that it's making it a non-normal use of Power Attack. The reason this is notable is because the Leap Attack description says "...you deal +100% the
normal bonus damage from your use of the Power Attack feat." It might come up if you can use Leap Attack as you'd like to, so you have to chat with your DM about it to make sure of how it actually interacts.
The good news with Combat Brute is it can be interpreted that it will work the round after a charge, including on other charges. So long as you continue to make charges each round, it seems you can continue getting the extra Combat Brute damage each round after the first.
However, remember that you're still trading accuracy for damage. The more damage you do, the more accuracy is going to be important since every time you lower your accuracy by 1 point it's going to effectively be a 5% damage reduction. You might get a better bang for your buck with
Shock Trooper. I know I've mentioned it already, but it really is a great feat since you don't have to worry about losing accuracy anymore and can do a full Power Attack. If I had the full stats of your character I could run them through a spreadsheet to see what your average damage would be for the Combat Brute vs Shock Trooper setups.
Be wary of the wording in Leap From the Saddle: "just as if the character were making a charge." It's a little too ambiguous and could mean the action was actually treated as a charge for all purposes, or that it's simply
as if it were a charge in that it grants a +2 bonus to attack but a -2 to AC, but nothing else to go along with a charge. So long as you qualify for Battle Jump though, it should be fine.
Last, but not least, the Gloryborn weapon template from DMG2 page 277 might be useful to you. A weapon it's applied to does an extra 1 damage on a charge, which will get multiplied thanks to your build. For 600g, it's a great investment.
If anything I've gone through is different than your interpretation, could you please go over it in detail? I've provided links to the feats and such, so you should be able to go through them thoroughly.
Until I know exactly what you guys have ruled works or doesn't work, I don't think there's much I can really go over.
