Q1:
4 attacks
Q2:
2 attacks
Q3:
7 attacks (not sure)
Q4:
For Q1:
SRD, Alter Self wrote:You acquire the physical qualities of the new form while retaining your own mind. Physical qualities include natural size, mundane movement capabilities (such as burrowing, climbing, walking, swimming, and flight with wings, to a maximum speed of 120 feet for flying or 60 feet for nonflying movement), natural armor bonus, natural weapons (such as claws, bite, and so on), racial skill bonuses, racial bonus feats, and any gross physical qualities (presence or absence of wings, number of extremities, and so forth).
So you can use the 4 claws of the Xill to attack.
For Q2:
SRD, Alter Self, just after wrote:A body with extra limbs does not allow you to make more attacks (or more advantageous two-weapon attacks) than normal.
So your 2 extra arms cannot be used with daggers, and cannot be used as claw attacks as they hold something.
For Q3:
See above, you attack with :
- Dagger in "claw" 1 (Primary)
- Dagger in "claw" 2 (Off-hand)
- Claw 3 (Secondary)
- Claw 4 (Secondary)
- Boot blade 1 (Off-hand)
- Boot blade 2 (Off-hand)
- Armor spikes (Off-hand)
I am not sure about the boot blades, as they are not in the SRD. I'll suppose that the boot blade only use one foot each, so you can use 2 of them.
(I found no limitation to the number of the "off-hand" attacks you can make.)
Note:
Using alter self, you gain the racial bonus feats, ie Multiattack in case of the Xill, so your secondary attacks are only at -2. TWF penalities does not apply to the secondary attacks.
It also seems the Xill entry in SRD is wrong, as the "4 claws" routine suffer secondary attack penalities even for the first claw ...