To me it doesn't sound too bad. You can start meats whenever you want. At 6 months I was feeding my son 3 meals a day and continue with that but I breastfeed him so I'm not sure how much he takes in as far as milk goes.
I don't always give him meats either. I'm not all that worried about it.
For the sippy cup thing. I bought the playtex sippy cups that have the 2 handles. They are great and they are no leak ones so he actually has to suck on it to get the water out. You could try them to see how it works for him.
My schedule at 6 months for my son was somewhat close to yours.
8am- breakfast usually oatmeal and/or a fruit
11:45-lunch usually a veggie and fruit
5pm- supper usually veggie, fruit and sometimes meat
Now that he's 8 months I took out the 2pm feed and I give him a snack with water. He also eats a lot of table food as well.