I was following and perhaps more importantly, understanding everything that you had written up until the point where topic sentences came in!
I've only been exposed such kind of topic sentences e.g. referring to the type of loss.
How do I create topic sentences from the contention? I thought that splitting it into types of loss e.g. emotional, identity was the way to go since they support the contention (?)... woops 
Here's the trouble with that:
Let's say I wanted to convince you that Broadmeadows was a lovely suburb to live in.
If I was like:
- Broadmeadows is lovely.
1. There is a nice house on this street which is lovely.
2. There is a convenient train station, which is lovely.
3. But some of the parts aren't lovely.
... I probably won't have convinced you of anything because I'm not fleshing out the idea of what 'lovely' is, I'm just piling on examples of loveliness instead of actually presenting you with
ideas.
So to take the following example:
Prompt: The characters in the play undergo extreme suffering. Discuss.1. They undergo emotional and psychological suffering.
2. They undergo physical suffering.
3. But some of them don't undergo suffering.
...see how that's kind of a weak/non-existent argument?
Instead, consider the following:
Prompt: The characters in the play undergo extreme suffering. Discuss.1. The play shows how suffering has profound and lingering effects on its characters.
2. Throughout the text, the characters have to come to terms with their suffering.
3. Ultimately, the characters who learn to manage their suffering and harness it to fuel their aspirations are rewarded, even though they must struggle to achieve this.
... now we've got a much clearer argumentative drive behind our essay, and it's much clearer what we're dealing with.
In short, don't just prove the prompt right in different ways so that your contention can be boiled down to 'yes.'
To be honest, I've always been taught to have a challenge/ rebuttal paragraph so I'm not too sure what you mean by scattering bits of challenges throughout the essay 
That's alright, I was taught the exact same thing. And then when I started Year 12 I was like, hang on, this makes no sense... why am I rebutting myself? And I've been raging against the machine ever since.
Think of it this way:
METHOD 1 (the mediocre method)
Take the prompt.
Come up with two arguments that support it.
Come up with one argument that goes against it.
Stick it all together, and you've got yourself an essay.
METHOD 2 (the super-awesome-mega-method)
Take the prompt.
Turn that prompt into a statement that mostly agrees or mostly disagrees (ie. 'Although... ultimately...' or something similar)
Come up with three body paragraphs that support this statement (so within each paragraph, you have your 'ultimately...' point that's your main contention, but you also have the odd sentence or two that acknowledges the complexity of the text by saying things like 'Whilst the audience may interpret X as Y, ultimately Davis implies...' or 'Though this may seem like an action motivated by X, the audience may also infer that it is in fact Y')
Method 2 > Method 1 QED

Thanks again for your help! Even though I have so many questions, I feel as though it's better than having none because it means I'm on my way hehe 
No worries! And you're totally right - better to ask and have your questions answered now than to get all the way to the exam and then realise you need to have things clarified

Again, let me know if any of the above didn't make sense or you want to run some ideas by me

OOPS i didn't read which forum this was on haha~ well i also get confused with SACs and everything lel, SAC is a hsc subject soo.. 
Man, the state education departments really needs to sort out their acronyms before we expand to South Australia or Western Australia, huh?
