Re: learning 2 arts at the same time
"Some can handle it, and others can't."
Amen to that. It depends on the person, and what else you study.
It seems Kendo would definitely help with your weapons.
Tai Chi has been very helpful with my aikido practice. Sometimes, I even try to incorporate one into another during practice. It also helps if your sensei has an appreciation or familiarity with the other art.