1) They are Outsiders, not humanoids even though they look humanoid it's only skin-deep.
2) All paladins must be Lawful Good.
Does humanoid angels, demons, devils etc... are they considered humanoid for the spells hold person, dominate person, or any spell that is for humanoid subtypes. Because under humanoid subtypes, it says that the creature has 2 humanoid arms, 2 humanoid legs and a humanoid torso.
No. If a spell specifies "humanoid" as a target, the target's type must be humanoid. Not just humanoid in shape, but humanoid in nature.
Humanoids are very similar to humans: A natural creature with the same general body shape as a human and few to no magical abilities.
Other creature types (especially outsiders) might have similar shapes, but they're nothing like humans in almost every other respect: They don't age, they don't need to sleep or eat, they don't have a soul the way human(oid)s do, and they tend to have a large number of abilities humanoids could only dream of (without class levels, that is). Their nature isn't natural (they're not creatures of nature), but elemental and/or alignment-based: While a human is a creature of flesh and bone, a devil is a creature of evil and order. Their mindset tends to be a lot different from humanoids, too, because all these differences.
Thus the spells require actual humanoids, not just something with the same shape.
If you are a paladin for a deity that is not lawful good, do you have to be lawful good?
Yes. Paladins must always be lawful good. That means that many deities will not associate with any paladins. Generally, the deities that support paladins are LG, NG or LN.
Paladins don't have an alignment restriction relative to their faith, so it's conceivable that you could be a paladin of a CG deity or something like that, but most of the time, it won't work because those deities are not suitable for paladins because of more things than their alignment.
Paladins also don't have to have a patron deity. You MAY, optionally pick one of the following deities as your patron:
Erastil, Iomedae, Sarenrae, Shelyn, Torag (all LG and NG deities) and also Abadar.