Another pic

and what I've been using

Are you growing these indoors or out? To be honest, they look perfectly fine to me - I don't see any obvious sign of disease and a few insect holes in leaves are insignificant. The peppers look like they are starting to develop fruit....are the tomatoes and others flowering as well?. Might still be a bit early for zukes.

You may have whitefly, especially if these are growing indoors. The plant extracts like your current spray are decent enough repellents but they don't often control pests otherwise (little kill potential). You may want to try sticky traps for the whiteflies or graduate to a contact insecticide like insecticidal soap.

btw, it may be helpful to go back into your member profile and adjust your location to reflect Australia. WA is the abbreviation for Washington State here in the US and it could be confusing :-) I was trying to figure out how you had tomatoes looking that good coming up on November!!

The brown discoloration on the stems is normal.

Just a little leaf miner damage but nothing to worry about. Plants get some bug bites and are no big deal.

The white bugs that fly when disturbed are white flies.

Yes, whiteflies.

And they live on the undersides of the leaves. If you spray, you must spray them there.