Oshi-zushi and other local Osakan foods

I'll be in Osaka for a few days and want to have a taste of the local specialities on offer, so the search for restaurants starts now!

I'm looking for a good sushi restaurant to try out Oshi-zushi (pressed fish and rice in a mould). I'll be staying in the Umeda area so I was wondering if I could find oshi-zushi nearby? Maybe in one of the department store restaurant floors? My friends who went to Osaka recently had a look in Dotonburi but they couldn't find any. Also, when is the best time of the day to go to department store restaurant floors for the least amount of time spent queuing?

Is the Takoyaki Museum in the bay area (Shimaya 6-2-61, Universal Citywalk) worth going to? Can you walk there from Osaka Aquarium? On this map there seems to be a bridge: http://www.bento.com/kansai/gmaps/8245.html

How do you find the indoor Meiji-era food theme park called Sammy's Ebisu Plaza? The address says Dotonbori 1-8-22 but I don't know how to look on the map for it. Are there any signs/landmarks that could guide me there? Is it a tourist trap and quite expensive?

Where can I find tasty crabmeat? Maybe even a crab set meal (for around 5000-7000 yen)? Is the restaurant with the giant red crab sign any good?

Please let me know your local speciality Osakan food restaurant recommendations! Kushiage, okonomiyaki - I love them all!

I recently walked through the Naniwa Kuishinbo Yokocho in Tempozan, and would have loved to try some of the foods, but I had no time:
http://www.kaiyukan.com/eng/restaurant/naniwa.htm

I'd like to try having kushiage food in Tokyo. I'm staying at a hotel near Tokyo Tower. Can anybody suggest a place ? Thanks.