I'm going to Rio tomorrow and I'll have the opportunity to revisit the Olympic Park since I'll attend the Rock in Rio music festival this weekend. I found this video images from this week:
From the video, we can see some things about the Rio venues:
The Rio Olympic Arena (Gymnastics), formerly HSBC Arena, is now called Jeunesse Arena. It's probably the most used venue of the Park, there's sports and other big events regularly there.
It's possible to see the damage at the roof of the Velodrome after the fire some months back. The repairs will cost "only" 200,000 reais (about 65,000 dollars) and will be paid with part of the money the music festival will bring - they will pay aproximately 1 million reais, which will also be used to transform the Carioca Arena 2 in a training center as a legacy for brazilian sports.
The Cariocas Arenas will hold the Game XP (a big eSports event), which will happen at the same time as the music festival.
The Future Arena (Handball) is still there, unfortunately. It was supposed to be desmantled already, but the new projection is for the next year.
The Aquatics stadium "skeleton" is also there. Both pools (competition and warm up) were dismantled many months ago and will go to other states that don't have 50m pools. Unfortunately no one seems to be interested in the "junk" of metal around it - so far that the idea of dismantle the arena might be scraped in favour of doing another thing using the structure (a smaller football field, a recreational aquatics center, among other ideas, have been suggested, but nothing concrete so far).
The Tennis Center hosted some beach volleyball matches this year and I hear is in talks to host future ATP events in Rio.