I happened to be in a suit because we did it on a Friday evening on the way home from the office, but you can wear whatever you want.
We applied for the Dependant's Visa for my wife on the Saturday morning about 15 hours after we got married. We did take a couple of photos of the 5 of us (couple, witnesses, solicitor) at the solicitor's office and made quick printouts at home to submit with the application.
The more evidence you have of the length of the relationship the better. The documents you suggest are good, and better than we had (we had nothing in joint names for example). If you have photos of you with each other's families I guess that is good (although obviously ImmD has no way actually of knowing who is in the photos) with you. Any photos which are obviously older are good - for example if you used to have very short hair and now it is long.
In my case it was this area that they pushed back on and I had a couple of rounds of submitting further documents. I remember that the last thing I submitted was a printed of a Skype log going back a year or two!
Joint tenancy agreements I reckon gives you a very strong case, but basically submit anything you think strengthens the case. Every time they come back to ask for more adds 2 weeks to the process.
Finanlly, I have never heard of any couple in a genuine relationship being disbelieved by ImmD. The only grounds I have heard of for rejection is insufficient financial means for you to support the Dependant, so don't neglect that area. But if you have accommodation here and an income of, say, $20,000/month or more (in the absence of kids) then that shouldn't be a show-stopper.
Assume at least 6 weeks for the application to be processed. It might come a little sooner, but then again ours took 10 weeks in the end (we didn't have such strong evidence of the length of the relationship).