I've been on a couple different remote teams in my career, each with a different expectation for collaboration.
A continuous chat group can be helpful depending on the culture. Sometimes all it takes is for your manager to be in the chat and then it's a dead chat.
Weekly v.s. daily stand-ups: I definitely prefer daily. A week can be a long time.
What I think is most effective for building a virtual team together is having different people pairing off to help another or to tackle a task together while on a voice call/screen sharing. Chat doesn't always cut it when you're working, and you might have a very different experience with a co-worker when you're on a voice call than when communicating through chat or email.