One is then supposed to conclude (incorrectly) that the visual experience is an illusion.

I'm willing to be incorrect, but my understanding of indirect realism is not that visual (or auditory e.t.c.) experience is an illusion per se, but more that it is not the exact same as the object that is experienced. If I perceive a cat on my windowsill then that is a mental event that is completely separate from (although far from necessarily an inaccurate representation of) something real.

Is hate an emotion, or is it more of an attitude, or a judgement?

Hate is a feeling, so an emotion. But it might be augmented or brought about by thoughts, attitudes or judgements - no matter whether true or untrue.

Is hate more irrational or logical?

If you accept what I said above about hate being a feeling then it is irrational by definition since the definition of 'rational' is essentially a thought that uses logic. A feeling is not a thought and feelings don't always occur for logical reasons. Therefore they are irrational.

Does hate serve a purpose?

If you accept evolution (as you say you do and as I do) then it almost definitely serves a purpose since so many creatures have a capacity for it. It must be advantageous in some way otherwise it wouldn't be such a universal behaviour.
My opinion is that it allows us to protect our own interests more effectively.

Do love and hate always express themselves?

Sorry, I don't understand?

Why is it that both love and hate can result in both heroic and evil actions?

Whether an action is heroic or evil is extremely subjective imo. But if pushed for an answer then I would say that hate is an emotion that can cause us to push back against perceived injustices, so can therefore be seen as a good action coming from an otherwise negative emotion.

Which one has the wider radius of effect?

Sorry, I don't understand the question here?

Is hate what happens when someone is not loved?

If you accept what I said earlier about hate being an emotion that helps us protect our own interests then you have to accept that hate can occur for other reasons besides not being loved. For instance someone could just be a bit inconvenient to you, getting in the way and making your life slightly more difficult, so you would be inclined to hate them so that they might stop being so inconvenient

Is hate a stronger force than love?

How could you ever quantify this? For a start, the strength of a feeling of love or hate can vary significantly, so I might ignore my mum if he she won't stop talking about boring stuff (strong love beating a weak hate) but I might not forgive a violent criminal if they mugged my mum in the street (non existent love for some random guy Vs strong love for my mum.
Basically, I guess I'm trying to say your question is too loose to be answered in any meaningful way.

Are destruction and construction two sides of the same coin?

An action that improves one person's life might come at the expense of someone else. So yeah, I suppose it's not completely clear cut. Bit things never are.

Is hate ever positive? Is love ever negative?

Is there a larger size than large? Is there a smaller size than small? Is there something you can compare something short against so that the short thing looks long? As a UK citizen if I'm in Australia then is my 'up' here their 'down'?
Has science helped the world? Has science hurt the world?

The point is that you're question is too binary. Too one dimensional. Cases could probably be out forward for cases where hate is positive and cases put forward where it is negative. You could probably put forward cases where it is both and the same time. And the same goes for love.

I'm not sure. We can delay these things in the expectation of future happiness but just as the happiness from sense pleasure doesn't last, I think the same goes for less obvious things. For instance you could spend long, hard periods studying for a qualification. (i.e delayed gratification and making sacrifice) but the 'high' from achieving your qualification will fade away as well, over time.

I'd appreciate if you could put forward your exact view on the subject so we can compare and relate?

I believe that Sense-pleasure and fulfillment are different methods to the same end. Sense-pleasure can lead to a (temporary) sense of well being and fulfillment. For instance, can you not say you feel fulfilled after eating a delicious chocolate cake? Do you not feel your stress melt away while lying down in the sun for half an hour? My point is that you feel peaceful and at ease in the wake of sense pleasure. So pursuing sense pleasure and pursuing fulfillment are just two methods for realizing the same end. The end of relief, peace, fulfillment, ease, well-being. In short, Happiness.

The problem is that, as we've both agreed on, is that sense-pleasure is not sustainable. However, at the same time, it's what we've evolved to do. We've evolved to seek out pleasure at every opportunity. As I said above, this is great for the survival of the species but tragic for the individual.

What Happiness is there in life if we are constantly chasing after more, more and more?

Do you think (honestly) whether we have the option of jumping off the treadmill? refusing to play the game and looking elsewhere for fulfillment? Or do we have to be slaves to our desires for the entirety of our lives?

Thanks for talking to me about this :)

I'll reply to your second point first:

"Is there a choice?"

My answer is: Maybe?
For instance Buddhists believe lasting happiness (i.e. peace) can be attained by letting go of attachment to things. Maybe some form of practice could 'rewire' your brain or prove more fulfilling than chasing things, eternally on the treadmill.

Reply to your first point:

" 'Mechanisms for happiness' is an odd distinction and could probably use clarification."

My working definition is, as stated above, that Happiness is the sense of release and rest achieved by various means. So a mechanism for happiness, is anything that brings about that state of ease. It might be the relief of hunger by eating, for example.

" Is happiness sense pleasure? Is it a sense of well-being or fulfillment?"

That is really making me think. I guess I'd agree with you that it's well-being and fulfillment (I'm assuming that's what you believe???). Sense pleasure provides that - Just only for a short while. Finding lasting, stable well-being and fulfillment without relying on sense-pleasure sounds like a much more realistic thing to achieve...