Re: kendo, Iaido and aikido
A year ago I would have said do both.
Now I'm not so certain.
It may be prudent to, instead of taking up a second art, invest more time into the one you're already studying. If you've got lots of time on your hands to train, go ahead and take Aikido too. But if you're strapped for time and serious about development in kendo, you should focus on that. You can always take up Aikido later. you have the rest of your life to explore new arts.
Aikido will come easier if you already have a firm grounding in sword art.