Maybe I explained myself badly, when I said "non-essential" (though I do think I explained what I meant by that, right after?).
Obviously Ukemi is quite essential to the practice of Aikido, I mean that it's not something special just to Aikido, or something that can only be explained by your Sensei. Of course, once I start, there will likely be changes that have to be made, variations that has to be learned, and so forth, but I see no reason why I can't start the basic practice myself
With Kamae, again, I do not expect to "perfect" that by myself, in any way, but again, it can't hurt to get the basics down. I do plan on practising Yoshinkan, which is lucky in this case, since (as far as I've been able to see) the style is very strict on posture, so chances are there won't be too much
of a difference in what I can learn from watching/reading, and what I'll learn in the dojo.
On fitness, I'm currently working out 4-5 days a week as it is, mainly cardiovascular exercises with Kettlebells, but also some resistance training
People focus a lot on the fact that I plan to "dojo hop", but seem to have missed why
I said I was going to. The reason is that I plan on taking (another) year in Tokyo, once I finish my Masters degree. Naturally, I will have to find a different dojo there, than the one I train at in Denmark. Not much of a choice, unless I don't go. It's not like I plan on jumping between dojo's just for the heck of it!