i never had any luck with oranges. i don't recall ever seeing any birds go to them the few times i put them out. there are several other songbirds who will eat grape jelly...mockingbirds, catbirds, i have even seen hummingbirds sample it. and alas, my dozen or so red headed woodpeckers have discovered it so it doesn't last long and when the jelly feeders are empty, the orioles sit on top of the shepards rods and stare into my windows. LOL
as for ants, at least on your hummingbird feeders, put a gob of vaseline where the hanger meets the top of the feeder. ants won't cross the vaseline. if you have a problem with bees bothering your hummingbird feeders, spray all around and over the feeding ports with olive oil flavored vegetable spray. don't ask me why it works but it does and it doesn't faze the hummingbirds in the least!
the only seed i put is is black oil sunflower seed. i never use any of the mixed feeds or suet cakes (other than one made especially for woodpeckers) because i have bluebirds nesting in my back yard nest box and i do whatever i can to discourage house sparrows.