There seems to be a buzz on Youtube about this subject and I thought I'd bring it up too. So, mixing pantheons (meaning you work with goddesses and gods from separate cultural and national backgrounds, or even saints, together) or not mixing pantheons (meaning you work with gods and goddesses from the same background for example Celtic or Norse). Some people say you should NEVER mix them together as on the other hand, others say you can't tell people what to do or that what they do is wrong (for example, if you work with Freya and Kali at the same time).
My mind is equally divided with both parties, as I see it eventually comes down to intuition. Whether you mix them or not, you usually follow you own gut. If you feel more than just one goddess or god call you then why not take the hint... However, if you feel like you only need to stick to this one deity who requires all your attention, then by all means, go with it. But not all practitioners (especially newbies on the field) have that developed gut feeling and they tend to make decisions based on ideas rather than instinct. For those, it'd probably be more safe to stick with the code, at least for a while - that is to say - not mixing pantheons. In brief, my view is; Do what you do, but know what you're doing.
Of course, one options is, that you don't even have to work with any particular deity or deities. Or you could use generalisations such as Goddess and God, Lord and Lady or whatever you come up with. Use your own names/expressions and in that way, make way to whoever wants to be with you.
Just relax, let go, and don't fuss about it. :)
That's for now, blessed be!
P.S: Have a magical fullmoon!