G'day Maree,

A non-waterproof fabric cannot be made fully waterproof. Most waterproofing sprays are designed to revive the already existing durable water-repellency coating on the fabric, you can use some waterproofing sprays although they will not completely make the fabric waterproof. 

G'day M,

No, they haven't really.  The frames themselves are the same and haven't changed with the exception of adding the yellow 'hydroflow' arms in the corners to keep the canopy taught.
I've never heard of these gazebos collapsing at all, unless the weather is extreme and the frame blows away.  Potentially get in touch with our customer support team and they can talk through the issue - you may have something broken or not quite right with the set up.

G'day Phil,

Yes, ultimately the frame and attachment points are the same across Oztrails 3.0 gazebo's - you shouldn't have any issues.

G'day Mike,

As we've mentioned in the specifications, Oztrail haven't provided any waterhead rating or waterproof testing on these gazebos.
Whilst these Gazebos may mostly protect short bursts of rain and light showers, Oztrail don't provide any guarantee.  

G'day Ken,

Yes, they will fit no worries, you'll just have to make sure the walls go underneath the canopy's four corner extensions.
Hope that helps.