I'm working on both a novel and a webcomic (both fantasy), how okay is it to use the same elements in them?

The novel and the webcomic are not in the same universe or world, and are different stories. I haven't done much work yet, they're both in the early stages of conception and working out plot, world, and details.

Both are very fantasy world however, and I wanted r/worldbuilding's opinion on how good or bad it would be to use some of the same fantasy elements. Random examples: fish 'swimming' in the air, cats with gems on their forehead, giant horse-sized dogs used as mounts, some similarities between the races, common bestiary, etc.

It would be perhaps maybe possible to have the two worlds being the same universe, and have one of the stories happen at very different times to explain the big differences between the two, but I am a bit hesitant to do so. The novel happens completely on this fantasy world, all of it, whereas the comic is two characters who get mixed up and sent to each other's worlds (one being Earth, the other being a fantasy universe). How okay/good/bad would it be to have the two stories in the same universe, but happen ages apart?

Thanks r/worldbuilding!