The survey questions really depend on your goals, so suggesting specific meaningful questions is not really feasible from the outside. Reaching your goal of 1k may not be simple through Bitcointalk (not that easy to get answers to surveys), and repetitive yearly takes of the survey by the same people, to get a long range vision of habits, is even more unlikely.
I’d try to do it all in one survey, with some meaningful questions focused on the short term, and some on the mid/long term or history of the participants.

In terms of Exchanges, you could also consider some of those missing from your list that are listed here: https://coinmarketcap.com/rankings/exchanges/