I think it will make sense to give something that is not too personal, since they are not really your friends yet, and also something that they can use. maybe you could try giving them one of those handicraft plant containers, that can be placed outside the door. these can be used dry as well as with water, and they can also use it as a decorative piece for their new home.
you can gift them a fun key holder that they can use on an everyday basis. also, a quirky lamp would make a fun gift option, as they can use it for light or just as room decor.
i think you can give them a set of mismatched funky tea cups. instead of the regular tea set that has all matching tea cups, the different ones always make a colourful statement.
Get a showpc etc like a candle stand
pictures or wall decorationitems
paintings
❤