Mandarake (say "Mun-dah-rah-keh") stores are child-friendly AFAIK, but then again, I only looked at Transformers. They may stock Ecchi/Hentai stuff, but I never saw it. But if you stick to the TF sections you should be right.
If you want to ask for Transformers, say "TORANSUFOOMAA" (say "tor-run-soo-for-mah"). A lot of fans/collectors abbreviate it as "Torafo" in casual conversation.
Never tried to have an item delivered to a Japanese hotel address.