Hello @Lunar_Witch,
Foxes are lovely creatures and, in some traditions such as Shinto, believed to be messengers of the gods. It’s exciting for them to keep crossing your path! 
I’d personally say that an animal doesn’t have to be traditionally associated with a particular deity in order for them to carry a message or be symbolic of something. Our bonds with the divine are very personal, and deities exist beyond the limitations of the physical world - folklore and legends show us that deities can manifest or send messages in various ways. I personally believe divine forces will send messages in whatever ways They feel will best get the message across to its intended recipient.
That being said, there are reasons why certain deities are associated with certain forms, animals, symbols, etc - and using those associations would make it easier for the recipient to get a message. As such, I think you’re right for considering other possibilities, too!
Possibly! You’re right about the Loki association - foxes have a reputation for being “Trickster Spirits” in some cultures, so Loki or any of the trickster deities could be worth looking into.
Personally, I think foxes and my mind immediately goes to Inari - a Shinto deity of agriculture and business who is sometimes depicted as a fox, and who utilizes foxes as Their divine messengers 
This is a great question and, from similar discussions in the forum, it seems like the overarching answer is usually. It will depend on the deities and Their relations with one another, your own priorities (such has having a patron/matron or fulltrui), and potentially creating different altars and/or practices with each deity.
I’d recommend taking a peek at other discussions on the topic, such as these:
The “Who Is It” deity spread is fantastic for getting answers about a deity’s identity, but you could use other methods of divination or a deep meditation.
Wishing you all the best - if it is another deity, I hope you can discover Their identity. And if it’s a message from a current deity, I hope the deeper meaning becomes clear for you too! Good luck and blessed be