The rules on Psi-like abilities says they behave the same as powers aside from the lack of initial costs, but does that rule out the ability to spend power points on them to augment them? I'm mostly looking for a general consensus here; the book doesn't explicitly say you can, but doesn't exactly imply you can't, either.
No, they are augmented automatically up to their Manifester Level
You don’t need to actually spend power points on psi-like abilities; they are automatically augmented as much as they can be for their Manifester Level. From the SRD Psionic Monsters – Psi-like Abilities:
When a creature uses a psi-like ability, the power is manifested as if the creature had spent a number of power points equal to its manifester level, which may augment the power to improve its damage or save DC. However, the creature does not actually spend power points for its psi-like abilities, even if it has a power point reserve due to racial abilities, class levels, or some other psionic ability.
Odd place for that rule, but there it is.