That's because we explicitly used Transformer characters, likenesses, names etc. It was because at the time I mistakenly thought that Hasbro AU had given me approval -- it was an honest mistake and not done intentionally. Hasbro understood this which is why they took no action other than a verbal warning.
I'm not an expert in intellectual property law, but isn't there some kind of 'fair use' thing where if you change a certain proportion/percentage of an image, then it's no longer their property?
Hasbro does the similar things for trademarks they don't own, for example the Generations Straxus toy was called "Darkmount" because Hasbro couldn't secure the rights to the name "Straxus." Likewise "Jazz" is called "Autobot Jazz", except in Alternators where they couldn't even secure that name (because I think that toy also falls under the category of replica car), so they had to use the name "Meister." IDW's introducing a character called "Circuit Smasher," which appears to be their version of "Circuit Breaker" - a G1 character still owned by Marvel Comics (there's speculation that Circuit Smasher may be a relative of Circuit Breaker rather than being Circuit Breaker herself... himself... umm...)
The comics and posters should be easy enough to do if you tweak the character models enough - as Paulbot pointed out, Marvel/Sunbow did the same thing in the G1 comics/cartoon... look at Jetfire/Skyfire -- they had to make the comic/animation model look drastically different from the toy otherwise they would've been sued by Harmony Gold for "ripping off" Robotech.
As for the toys... I think it should be okay so long as you explicitly state that you're giving them away as freebies. As I mentioned before, it's been previously done before with BotCon exclusive toys that 3H weren't able to secure sales rights for like Rook and Tap-Out.
But anyway, if any of this concerns you seek professional legal advice before proceeding. In NSW there's a service called LawAccess which gives free legal advice -- I'm sure there are equivalent services in other states.