There's no rule that a player can only play 2/3 events at the Olympics. Andy Murray played all three in 2012 and Federer has already confirmed he'll play with Hingis in Mixed Doubles.
Final set between Troicki and Dimitrov in the Sydney final was something else. Troicki, of all players, came up with a miraculous backhand pass to seal championship point, after saving a championship point of Dimitrov's with a desperate backhand volley. They both made some tense UEs towards the end, but it was a great watch.
Cornet v Bouchard in the wind at Hobart was a non-event. Genie had no idea what to do, and Cornet knew it.
Some good matches scheduled on day one, including Djokovic/Chung, Kohlschreiber/Nishikori, Tsonga/Baghdatis. Other young guns in action include Coric/Ramos-Vinolas, Edmund/Dzumhur, Thiem/L. Mayer, Nishioka/Cuevas, Rubin/Paire. On the women's side there's Mladenovic/Cibulkova, Vinci/Paszek, Schmeidlova/Kasatkina, Bencic/Riske, Hantuchova/Kuznetsova, Serena/Giorgi.