I would add a bit of Aikido history to the welcome page. Just speaking from personal experience, while I knew Aikido was a Japanese martial art, I didn't know much of anything beyond that. Additionally, after some background information about Aikido in general and who O'Sensei was, I would also include specific lineage info. While all new students may not know enough to ask about lineage, some of them will want to know.
Not the welcome, I think. If you start putting all the stuff you think they ought to know or might like to know under "welcome", it's just like marking all your tasks as "top priority". We all know what happens then. A separate section about aikido, or just a paragraph on the "about our dojo" section, should be sufficient, with references if they want to read further.