First, thank you both so much for replying. Now, to answer:
Natepig - Yes. She did this a few months after LBP1 came out. Everything transferred fine, except everytime she loaded she received this:
"WARNING! Your profile has been copied from another user. You can proceed but you will not be able to unlock any Trophies. If you wish to unlock Trophies then please quit the game and delete the profile from the Game Data Utility before rebooting"
While she was upset about it (after all, who wouldn't want to win trophies?), she dealt with it since she at least didn't have to start over and she was more focused on the items than the trophies.
The problem is now with LBP2. She'll load it up and instead of it importing the LBP1 data immediately like it's supposed to...it doesn't. And when she gets to the Pod on the "new sack" and tries to import it that way, it says she can't because the data was copied from another user (her father's PSN--as mentioned, she didn't realize the whole way a PS3 worked at the time so she never realized she was logged in as him...she made her PSN when setting up her PS3).
daveshooter - I pretty much got the first two questions answered above. XD Like I said, she had no idea about how the PS3 worked, so the files were just copied from the save data onto a USB and transferred.
This was done in December 2008. The games are all completely updated--I don't know when my dad last used his (or if he still has his old PS3), but the PS3 doesn't seem to be an issue--it seems to be the fact that she accidentally played it on his PSN when she first got the game that has caused the problems.
She wouldn't mind replaying everything to earn trophies--she would mind having to remake 55+ costumes, regetting every costume, making like 20-30 levels, and etc. Not to mention the community items and pictures she'd also lose.
As for the same firmware, I believe so? I honestly don't understand the question =( I'm sorry--we're both pretty bad at the technical terms.