Well, you could top up with more juice, and there's nothing wrong with that, but it will cause your clearing must to cloud up again & the overall fermentation will take longer. If you continuously top up with more juice, you'll have the same problem over & over and it will take forever to be done. If you're willing to wait a bit longer, top up with juice ONCE then let it finish up & clear.
You could rack to a smaller vessel.
You can use sanitized marbles to take up space in the carbouy (don't use steel bearings).
If you want to add fruit to a cider, I'd do so in primary & hit the whole thing with campden tabs. For the spices, I'd just save them for serving time, but if you want to add them to secondary, go right ahead; you'll want to use whole versions of them though, the powdered stuff can make a nasty mess. make a sort of "teabag" for your spices so you can easily remove them without having to rack again. Hope this info helps. Regards, GF.