I don't see how we can 'realistically expect' top 6. We can hope, wish and dream but not expect. A realistic expectation is best of the rest and even that depends on many factors. How quickly we bed in, how good Silva really is, how everyone elses transfers work out (will West Ham work or implode, are Leicester stronger or weaker ex-Mahrez, are Wolves really a threat...?).
Next season will be a different matter, but this season should be about settling the squad, adapting to a new playing style, re-connecting with the supporters and building for future. Anything better than 7th would be a huge bonus and rely on someone having an absolute mare of a season or us being exceptionally good. 8th/9th would be a little disappointing but even that may be ok if we see the football we want and it just happens that someone else clicks.
Also, nobody can expect to win a cup, there is the lottery of the draw, anything can happen. That said, I expect us to make at least try for a change.
7th and at least one visit to Wembley, that's realistic for me.