To answer your question without FLAMING you, I'm not aware of any cheats. I'd suggest that you unlock Boba on your own for your 5 yr old and then let them play in free mode. Some people can be so rude and forget that EVERYONE at 1 time was new to gamming.
Well ive unlocked Boba Fett. i tell you how to unlock him. You have to complete Jabba's Palace go to Eric's LSWTCS guide to find out how to complete Jabba's Palace when you have completed it you can buy Boba Fett in the Mos Eisley Cantina You can unlock Zam Wesell but only on the console versions of LWSTC. To unlock Greedo complete the Mos Eisley level in espiode IV to find out how to complete it go to Eric's LSWTCS guide when you have complete the Mos Eisley level you can buy Greedo to unlock Jango Fett complete disovery on kamino in espiode II go to Eric's LSWTCS guide to find out how to complete disovery on kamino when you have completed discovery on kamino you can buy Jango Fett to get the other bounty hunters complete the last level in espoide VI go to Eric's LSWTCS guide to find out how to complete the last level in espiode VI when you have completed the last level in espiode VI you can buy the rest of the bounty hunters that is how to unlock all the bounty hunters.
Just use Jango Fett, he is way cooler anyways (he has 2 guns instead of 1).
You could also enter the Debug code, and use it to go into the menu and unlock all the characters. So then you would have Boba Fett (as well as all the other characters). --- Toho's Godzilla Will Live Forever!
They are the only ways. But you have to have beaten them in a level to unlock them to be available to buy so... --- "I'm going to go do British things, like drink cups of tea and eat bangers and mash, that sort of thing...because I'm British"