Well this is strange for Australians. What we call tomato sauce is pretty much your ketchup (there is some ketchup available but it isn't really like yours I don't think).
But either way no. I wouldn't put Australian tomato sauce or ketchup on a pizza.
100% agree with Lostelle
One of the points of playing reborn is working with limited resources. No-one here is going to tell you how to get rid of those challenges and if you did you'd be somewhat ruining the point of the game. If you are stuck on leaders use the gym leader help thread here to get suggestions rather than trying to cheat.
People wouldn't be discussing "cheating in pokemon." They may get people to edit in pokemon for challenge/ mono type runs but this is completely different to cheating in items because you want them. Finish E15 then go and get the items you want.
He did work for Lysandre during the special so he will probably work for Team Flare at least for a little while. I think he'll work out that they are doing the wrong thing at some point and switch sides though.
Look- you're allowed to use monos I just wouldn't recommend it. Especially not Mono Fairy Micky. I love mono fairy but you'll never beat a steel leader. Bullet punch would kill you.
Juu
What items are you looking for specifically. Are there any ones that you want a lot because there may be places where you can find them past Agate.
You can't go back until you finish E15 though.
I never thought I'd say "Phew. I really didn't want to make some stupid ducks dance in circles. Circles are evil...". The things animations do to us...