I can't see it looking tacky as long as things are coherent. Sure, get a comforter that you like, maybe sheets in the other color, and add some pillows once you see how it all looks -- just not too many pillows, as I assume that fashion needs to yield to the exhaustion of late nights...

what colors are the walls in the room? flooring color? any window coverings?

do you have any bedroom furniture at all? since I assume you can't change the above, you will have to work around that first.

Photo 3 looks really nice. Neutral comforter with added color in the pillows and bedding. As with the picture bring in artwork, rugs and greenery that pull everything together.

Congrats on graduating and on your first apartment

These are horrible photos because I took them from a video, but this shows the wall color and the carpeting of the model apartment that they have. Since it’s a student apartment, the rooms aren’t too big.

Solid color comforter. You won't regret it. If you want pattern, either curtains, sheets, or get a quilt or quilted blanket. And wall art too, if you can put stuff up. In all your inspiration photos, the comforter is solid.

If the room is small, be sure you only use pillows on the bed that you actually use when sleeping. Otherwise, you will be jumping over them if you get up to go to the bathroom! And forget all the throws and other stuff - more stuff to take off the bed at night and put back on in the morning. You will be making your bed everyday, right? Keep it simple and that might actually happen!