Dashes are at the beginning of each question
--First question is a bit of a repeat for me. The following text bothers me:

"You do not receive additional natural attacks for a high base attack bonus. Instead, you receive additional attack rolls for multiple limb and body parts capable of making the attack (as noted by the race or ability that grants the attacks).

So say I am a level 6 druid with a base attack of 4 and I take the form of a large tiger. Can I preform both of the tigers attacks as a full round action even though I lack the base attack for multiple attacks? If I could still make all the attacks then what does having +6/+1 base attack do for me 2d20+modifiers for all attacks...?

--Secondly does the spell ant haul allow a wildshaped druid to bear a rider they would otherwise be unable to have?

Ant Haul
School transmutation; Level alchemist 1, cleric/oracle 1, druid 1, ranger 1, sorcerer/wizard 1, summoner 1

CASTING
Casting Time 1 standard action
Components V, S, M/DF (a small pulley)

EFFECT
Range touch
Targets creature touched
Duration 2 hours/level
Saving Throw Fortitude negates (harmless); Spell Resistance yes (harmless)

DESCRIPTION
Table: New Carrying Capacity

Strength Score Light Load Medium Load Heavy Load
1 9 lbs. or less 10–18 lbs. 19–30 lbs.
2 18 lbs. or less 19–39 lbs. 40–60 lbs.
3 30 lbs. or less 31–60 lbs. 61–90 lbs.
4 39 lbs. or less 40–78 lbs. 79–120 lbs.
5 48 lbs. or less 49–99 lbs. 100–150 lbs.
6 60 lbs. or less 61–120 lbs. 121–180 lbs.
7 69 lbs. or less 70–138 lbs. 139–210 lbs.
8 78 lbs. or less 79–159 lbs. 160–240 lbs.
9 90 lbs. or less 91–180 lbs. 181–270 lbs.
10 99 lbs. or less 100–198 lbs. 199–300 lbs.
11 114 lbs. or less 115–228 lbs. 229–345 lbs.
12 129 lbs. or less 130–258 lbs. 259–390 lbs.
13 150 lbs. or less 151–300 lbs. 301–450 lbs.
14 174 lbs. or less 175–348 lbs. 349–525 lbs.
15 198 lbs. or less 199–399 lbs. 400–600 lbs.
16 228 lbs. or less 229–459 lbs. 460–690 lbs.
17 258 lbs. or less 259–519 lbs. 520–780 lbs.
18 300 lbs. or less 301–600 lbs. 601–900 lbs.
19 348 lbs. or less 349–699 lbs. 700–1,050 lbs.
20 399 lbs. or less 400–798 lbs. 799–1,200 lbs.
21 459 lbs. or less 460–918 lbs. 919–1,380 lbs.
22 519 lbs. or less 520–1,038 lbs. 1,039–1,560 lbs.
23 600 lbs. or less 601–1,200 lbs. 1,201–1,800 lbs.
24 699 lbs. or less 700–1,398 lbs. 1,399–2,100 lbs.
25 798 lbs. or less 799–1,599 lbs. 1,600–2,400 lbs.
26 918 lbs. or less 919–1,839 lbs. 1,840–2,760 lbs.
27 1,038 lbs. or less 1,039–2,079 lbs. 2,080–3,120 lbs.
28 1,200 lbs. or less 1,201–2,400 lbs. 2,401–3,600 lbs.
29 1,398 lbs. or less 1,399–2,799 lbs. 2,800–4,200 lbs.
+10 ×4 ×4 ×4
The target's carrying capacity triples. This does not affect the creature's actual Strength in any way, merely the amount of material it can carry while benefiting from this spell. It also has no effect on encumbrance due to armor. If the creature wears armor it still takes the normal penalties for doing so regardless of how much weight the spell allows it to carry.

Ant Haul, Communal

School transmutation; Level alchemist 2, cleric 2, druid 2, ranger 2, sorcerer/wizard 2, summoner 2

CASTING

Casting Time 1 standard action
Components V, S, M/DF (a small pulley)

EFFECT

Range touch
Targets creatures touched
Duration 2 hours/level
Saving Throw Fortitude negates (harmless); Spell Resistance yes (harmless)

DESCRIPTION

This spell functions like ant haul except you may divide the duration in 2-hour intervals among the creatures touched.

--Thirdly could a water element enter Aqueous orb(spell listed bellow) and use wirlpool special attack then more the orb? If so wtf happens?

Aqueous Orb
School conjuration (creation) [water]; Level druid 3, magus 3, sorcerer/wizard 3, summoner 3; Bloodline aquatic 3

CASTING
Casting Time 1 standard action
Components V, S, M (a drop of water and a glass bead)

EFFECT
Range medium (100 ft. + 10 ft./level)
Effect 10-ft.-diameter sphere
Duration 1 round/level
Saving Throw Reflex negates; Spell Resistance no

DESCRIPTION
You create a rolling sphere of churning water that can engulf those it strikes. The aqueous orb can move up to 30 feet per round, rolling over barriers less than 10 feet tall. It automatically quenches any non-magical fires and functions as dispel magic against magical fires as long as those fires are size Large or less.

Any creature in the path of the aqueous orb takes 2d6 points of nonlethal damage. A successful Reflex save negates this damage, but a Large or smaller creature that fails its save must make a second save or be engulfed by the aqueous orb and carried along with it. Engulfed creatures are immersed in water and must hold their breath unless capable of breathing water. They gain cover against attacks from outside the aqueous orb but are considered entangled by its churning currents, takes 2d6 points of nonlethal damage at the beginning of their turn each round they remain trapped. Creatures within the orb may attempt a new Reflex save each round to escape into a random square adjacent to the aqueous orb. The orb may hold one Large creature, 4 Medium, or 16 Small or smaller creatures within it.

The sphere moves as long as you actively direct it (a move action for you); otherwise, it merely stays at rest and churns in place. An aqueous orb stops if it moves outside the spell's range.

--Question 1: Your +6/+1 is in druid form. If you attack in druid form, assuming you're using a weapon, you attack/attack.

If you take the form of a large tiger, you get all of the tiger's natural primary attacks. Let's say it's claw, claw, bite. You'd claw, claw, bite, all at your highest BAB, adjusted for your wild shape's strength modifier.

--Question 2: Absolutely. Assuming you could somehow bear a rider (pun intended) on a bear. If he had some kind of exotic riding skill or you were wearing a saddle or some such thing.

--Question 3: The water elemental would still take attacks from the Aqueous Orb. I see nothing in the spell description that says it ignores creatures of the water subtype.

I also don't see anything that says the water elemental could gain control of the orb in any way. Neither would damage the other.

I think, really, the only thing that would happen is a stalemate. On the good side, the water elemental is now protected from attacks from outside the orb. Consider it a stasis ball.

Fro question 2, the answer is probably "no". Whether or not a creature can be used as a mount has less to do with actual strength than it does with size and shape.

Sure, a medium sized bear can absolutely bear the weight of a human rider (for instance), but he doesn't have the room on his back to make it a comfortable (or even useful) ride.

Anatomy, far more than muscle mass, comes into play when determining suitability for use as a mount. (This is why those rules are determined using Size categories rather than Str scores.)

Now, once you've got the size thing worked out, then the Strength score does come into play, and if it's simply carrying capacity you're worried about, then there's no problem. But no spell is going to allow a Medium-sized creature to serve as a mount for another Medium-sized creature without special rules.

*Edit* There is one addendum to all of that: If your druid has the Powerful Build feat, then the Medium-sized creatures he/she Wild Shapes into can totally bear a Medium-sized creature as a mount, because Powerful Build specifies that it applies to carrying capacity.