The earlier in the day, the shorter the wait (generally speaking.) Now that the Flower and Garden is going on, the park will probably be a little more crowded and more people will be in the areas to line up for the Princesses around World Showcase.
Character Spot was literally a walk in when I did it a couple months back, but I know it's available on FP+, too.
I've had pretty good luck with meeting the characters with little waits (Poppins, Alice, Duffy, Mulan, Belle and Aladdin and Jasmine), but it just really depends on when you go. I did wait quite a long time for Snow White a month or so back.