Thales claimed water as his arche, but Aristotle says that he also said that "Everything is full of gods". Are those two claims in agreement?
Water, when poured into a vase, takes the shape of the vase; when poured into a hollow statue, it takes the shape of a statue. Then it's easy to go from here to think water is the arche of everything: in being infinitely malleable into all forms. Simply because Thales is reported to think water is the arche does not mean he thought actual water is the arche, but more likely something that is akin to water. First thinker on something usually does not have the language to express everything that he's meant, but usually borrows some analogous term. I suspect that's why the arche was also thought of as air and the boundless. The boundless is probably the most abstract term here.
However, in the above discussion a shaping hand is needed - to shape the vase, the statue, the form - and this is probably why Thales asserted that it was the gods that provided the shaping hand. The same goes for Pythagoras and then Plato. All of this is ontology as it reflects on the basic constituents of the world.
Water is the arche. Everything is full of gods.
They're consistent if only for the reason that they're not logically connected i.e. the truth/falsity one doesn't imply the truth/falsity of the other. It's like saying John Smith is English and quadrilaterals have four sides It would've been super-interesting if these two were somehow linked logically. Are they? I dunno.
One interpretation of the fragment you refer to (11 A 7 in Diels-Kranz numbering):
Some say that [soul] is mixed in the whole universe. Perhaps that is why Thales thought that everything was full of gods.
can be in the lines that something divine permeates the whole nature, which is in turn a logical consequence once you have discovered a unifying principle for it (water in this case), as Thales did. Note however that it is marked with an A, which means that it is a testimony, and not an explicit fragment (which are scarce for the Miletus presocratics). There are only testimonies of Thales' thinking, therefore we may only speculate about the exact content of it.
Nietszche's view on this on Early Greek Philosophy is also similar to the above interpretation:
Greek philosophy seems to begin with a preposterous fancy, with the proposition that water is the origin and mother-womb of all things. Is it really necessary to stop there and become serious? Yes, and for three reasons: Firstly, because the proposition does enunciate something about the origin of things; secondly, because it does so without figure and fable; thirdly and lastly, because in it is contained, although only in the chrysalis state, the idea: Everything is one [...] Thus Thales saw the Unity of the "Existent," and when he wanted to communicate this idea he talked of water.