Regarding Legos, do you have to have a lego surface to build on? We had a lego table a long time ago for littler kids but don't have it anymore. I'd rather not buy more furniture (like the big lego table) but someone told me I really need to have a lego surface for them to build on. I don't remember my brother having that but he wasn't hugely into lego's, so who knows.
Also, if he does happen to get into Bionicles, do those need to be stored separately or do they go with Lego?
I have the most genius idea for Lego storage ever. The Lego tray. See here.
Bionicles blend right in with Lego as they are Lego.