G'day Emma,

Yes, this is a great weight for hiking and one of our warmest and lightest sleeping bags with a comfort rating of −10 °C that should keep you toasty in cold Victorian and Tasmanian winters. You can also add a sleeping bag liner to add some extra insulation like the Thermolite Reactor Extreme Liner. This is a great quality option for winter hiking that is lightweight, packs down small, warm and insulating.

G'day Lilly,

Quilt comfort temps are just a best guess - they can't be physically EN tested like sleeping bags.  It's quite likely that if you were in a -7ºc sleeping bag you might have had a different experience.
Having said that though, the general rule of thumb is to go with a comfort temp of 5ºc colder than the coldest temp you expect to be in, taking that down to 10ºc colder if you are a cold sleeper.  This is to account for/and offset all the variables that can affect how warm you sleep.
With that in mind, if you are in 0ºc temps, a -10ºc bag would be ideal.
The other factor to consider is the R-Value of your sleeping mat.  If your mat has an R-Value less than 4, your sleeping bag or quilt won't perform to the advertised specs.
Bags with natural insulation such as down, have a greater application of use over a larger range of temps.  A -10 down bag can still be used year-round, especially when you have the ability to fully unzip and use as a blanket.
As the Flame series is ultralight, it cant be fully unzipped, so it will have slightly less flexibility.

I'd say for versatility it might be worth considering the Flame 3, and taking your quilt with you as an extra on trips where you're expecting super cold nights.  Layering an additional quilt over your sleeping bag to extend the comfort rating is a super common practice.  It allows you to have flexibility with your sleep systems year round, with the option to take either on their own, or both when you're needing extra insulation.

Hope that helps with your decision.

G'day Ken,

The Flame sleeping bag can't be zipped to another bag, they've been designed to be as lightweight and compact as possible, so they're not able to be zipped to another bag. The Traveller TR2 might suit your needs, you can zip them to each other. Otherwise, the Trek TK2 and Journey JO1 have the option to zip together and should suit your temperature needs. 

G'day Kerrie,

The regular length is designed for maximum user heights of 170cm, so you should be fine in the regular length. I'm 165cm and also have US10 feet and find the regular length a good size, with plenty of foot room.  The Flame Fm4 will give you a slightly warmer temperature rating for the same weight bag, due to the smaller bag size. We'd generally recommend going for a women's bag as it will give you a little more hip-width which can be handy.