The word, pantheon, comes from the greek, Pan Theos, meaning "All the Gods." I suppose that would be a good name for the Great Spirit which encompasses them all. Most people, when they turn to Magick, decide on a pantheon of Gods and Goddesses to worship. I'm not going to tell you my thoughts on such an idea here, but instead, deal with more of a controversial method of using Gods and Goddesses from multiple cultures at once.
Every culture identifies the Divine by their own archetypal concepts and ideas. With this in mind, it's believed that these energies which come from such thoughts should only remain to those cultures from which they originated. That's an interesting thought, but there's nothing which states that energies cannot be combined from multiple cultures.
To be honest, there's nothing wrong with mixing pantheons. It's been done throughout history, when one culture defeats another. Take a look at Christianity for a moment. They often took Pagan Gods and converted them to their own devils and demons, or even as saints. Voodoo is filled with Catholic imagery which they use to express their own god-forms. The idea of Gods and Goddesses remain true in archetypal form, and what you decide to name them has no affect on the energies you use to invoke them.
Another example is the Egytpian god, Bess, whom isn't Egyptian at all. Often, names have been taken from neighboring religions, and used for their own needs. A good example of this is seen in the Roman and Greek pantheons, who have similar, if not the same, divinity, just differing names. Many of the Roman Gods and Goddess came from the Etruscans, who were their predecessor.
There are no rules against mixing pantheons. Feel free to experiment, and never allow anyone to tell you otherwise. Archetypes remain the same in their basis, and any name can be given to them. Remember that these are name by which the Gods and Goddesses can be identified. If, for example, if you use Osiris to represent the God, and Hera to represent the Goddess, there's nothing which states that these enegies will clash, simply because they belong to religions not connected to each other.
The purpose for DEN OF GODS was to show you that these ideas remain the same, no matter which path or cultural religion you choose to follow. Spirituality is made up from a foundation which archetypal imagery is the source for all things mental and emotional. I've said it numerous times that spirituality is an individual pursuit. Enjoy making new discoveries, and let no one stand before you.