Re: learning 2 arts at the same time
While I think that a 10 year minimum is pretty over the top, I would reccomend sticking with just Aikido for a little while at least. The instinct is to say that Kendo will help with weapons but I'm not convinced that's the case. From what little I've seen of Kendo it's quite different to aiki ken and may well cause confusion for you. With any art I'd reccommend getting a solid understanding of the basic movement before cross training anything else.