What are you fermenting in? Standard HDPE brew bucket I assume?
I'd throw away that cleaner stuff you have, especially if it has a Brewcraft sticker on it.
All the brewery related cleaning I do is done with the unscented napisan (or similar brand) in hot water, followed by a hot water rinse until clear of all residue. Sanitising is then done with StarSan, mixed up at 1.5mL per Litre of water - at this concentration it sanitises in about 30 seconds and does not need to be rinsed.
If there beer smell isn't to strong I wouldn't worry about it, the next brew will cover it up ;-)
I'll endorse Glen's comments. I use Clorox Oxy Magic as a cleaner. All of the Oxy cleaners use Sodium Percarbonate as the active ingredient which breaks down easily so is environmentally friendly, if you care about that sort of thing. Napi San has 14% active ingredient whilst Clorox has 33% active ingredient for about the same price. StarSan rocks.
Don't worry about a small amount of residual beer smell, plastics will absorb some smell but it won't hurt your next brew.
Napisan or similar is. You're looking for something with a 'percarbonate' as an active ingredient. You want the unscented/sensitive-skin version, otherwise those smells will be leached onto your equipment.
StarSan is only available via homebrew stores. Where are you located?
Great Expectations in Lower Hutt do carry StarSan (it's where I buy it usually). Though he seems to often only stock one at a time as he is often out of it when I stop by (and I've only ever seen one bottle on the shelf).
You can also mail order it from Brewers Coop in Auckland.
Not usually but I can't see why not. Too long of a soak may cause some oxidation though, but it wouldn't be a biggie. Most of my copper stuff is rinsed with water straight after use so I don't really bother 'cleaning' it as such.
A side note - vinegar is awesome for cleaning copper, some vinegar and water in a pot, chuck your copper in, boil for a while = shiny copper.