Agree x2. I don't think there's any real reason why not. It's not like Disney hasn't dabbled in inter-species romances before. Off the top of my head I can think of:



Who Framed Roger Rabbit: The titular rabbit's wife is a human...

The Little Mermaid: A mermaid and a human.

Beauty and the Beast: A chimera and a human.



Admittedly the last two ended up with the non-human component of the relationship becoming human in the end, but that doesn't change the fact that they fell in love outside of their species to begin with.



And for those people that say "Why Does EVERY Disney movie have to have a romantic subplot?", to which I counter with the following.



Only one of the previous 4 Disney movies had a romantic central plot:



Tangled: Eugene/Flynn and Rapunzel, romance was central to the plot and characters

Wreck it Ralph: Small romance subplot between the two tritagonists, but barely touched on, not central, and not critical. The relationship between the male and female protagonists is friendship.

Frozen: Romance between Anna and Kristoff, but downplayed and turns out to be a big red herring, and the true message is sibling love.

Big Hero 6: No romance whatsoever.