Your question is not very clear and your grammar is hard to read. Could you please clarify the question?
Ok, I think I am understanding it now.
Yes, you are allowed to use a lance as a one handed weapon as long as you are mounted. A mounted lance user is a very viable build. However, if you choose to wield a lance one handed, then your are wielding it one handed for all intents and purposes such as the bonus damage from power attack. This FAQ states you get full power attack bonuses as if it's still being wielded with two hands.
Yes, you can two-weapon fight with a lance and shield, which is normally very difficult since a lance is a reach weapon and a shield is not, but you can use lunge to make it work.
I would suggest looking up feats such as spirited charge for this build.
Actually CampinCarl there is an FAQ that clarifies that the lance specifically counts as being wielded two handed, even when being used 1 handed while mounted. So he would get to use power attacks as though two handed and get 1.5 strength damage.
He can also hold and wield a shield and potentially TWF with it, but doing so will be very tricky.
Lances are reach weapons, meaning they can't attack adjacent targets. Shields aren't reach weapons, and under most circumstances you wont be able to hit the same target with both a shield and a lance because a lance can only hit 10ft away and a shield can only hit 5ft.
There are ways to make it work, but IMO it's probably not worth it.
If you're using a lance you're better off just building a charging lancer build. If you're wanting to TWF from a mount, you're probably better off just playing a ranger with the shield master combat style (ranger also gives you a mount) and not using a reach weapon in your other hand. Remember, when you move you don't get a full attack so you can't get the charge damage bonus on a lance and TWF at the same time.
You really need to decide to either be a mounted charger, or decide to be a TWF that just happens to be mounted.
Oh really? I must have missed that FAQ. I've found it now and have edited my previous post. Good find Claxon.
A blood rider bloodrager with the aberrant bloodline wouldn't have much trouble with the reach issue.
Actually CampinCarl there is an FAQ that clarifies that the lance specifically counts as being wielded two handed, even when being used 1 handed while mounted. So he would get to use power attacks as though two handed and get 1.5 strength damage.@Claxon, can you link to that FAQ? All I can find is that the -1/+3 power attack progression applies to the lance while mounted (HERE), but this FAQ seems to imply that I do not get the 1.5 STR bonus. It does not make sense to me that the +50% applies to Power Attack, and not to STR, but that does seem to be what those two FAQs imply.
The second FAQ doesn't apply because of very specific wording.
A lance deals double damage when used from the back of a charging mount. While mounted, you can wield a lance with one hand.
That second FAQ specifically deals with abilities that says something along the lines of:
Jotungrip (Ex)
At 2nd level, a titan mauler may choose to wield a two-handed melee weapon in one hand with a –2 penalty on attack rolls while doing so. The weapon must be appropriately sized for her, and it is treated as one-handed when determining the effect of Power Attack, Strength bonus to damage, and the like.
The important part is whether or not the ability says "is treated as one-handed". I think all similar abilities say that, except for the lance's specific ability.