I'll try to balance the two... This may be due to my beginner level,...Do you have any thoughts on which (if any) karate styles might harmonize with the circularity, for lack of a better word, of aikido, the best?...
Not sure if you're still interested in this topic, but just in case, and FWIW:
My opinion is that very few people can train in two different (at least at basic level) arts/ systems, and be excellent at both (either?).
Not sure why this is - could be that the sorts of people who try it aren't made for either (harsh, yes)- or could be that it's a case of 'chase two rabbits- catch none
My suggestion? If you want to train traditional Karate, and you feel it suits your body type/ instincts- try Goju, or another Okinawan style if you have access to an experienced and true teacher.
If you want to train Aikido, just train Aikido (same caveats).
You mention the fun of kicking. While it can be liberating or give you a free or empowering feeling to strike in training Karate or other arts, this is not always an indication that you are developing a practically applicable arsenal of behaviours/ techniques (which can also be developed in Aikido IMHO).
Having said all that!!
I am no expert and enjoy typing- so take it with a grain of salt hey?