In my opinion – probably just something to keep an eye on for awhile. My buns scratch their ears all the time, especially after I pet them as if they are trying to get rid of my human germs
If the scratching gets to be alll the time and they are shaking their heads around a lot as if they are trying to get something out of their ears, then I would definitely recommend a vet visit since that could indicate some kind of ear problem. The fact that their ears are looking good is a good sign – but keep checking and monitoring for any changes in their behavior.
Sneezing can be caused by many different things. Sometimes it can be dust in the hay, strong scents or perfumes, or any other list of things that irritate their noses. Is there any discharge when your bunny sneezes? That is something to look out for and something that probably merits a trip to the vet. You can tell if they has been discharge because your bunny will either have damp/stickiness around the nose, or have crusties from dried discharge.