If it's fixed in newer OPL but not the MMCE one, it's possible to load from USB, SMB or UDPBD using the newer versions.
But she should already have FMCB if she can use OPL. Why the need for FreeDVDBoot to get FMCB?
Also, FreeDVDBoot is not supported on all phat models, only some DVD player version. If it's supported, for most games it's possible to patch the game ISO and burn it to play it right away from the DVD.
https://www.psdevwiki.com/ps2/FreeDVDBoot_Compatibility_List
MechaPWN doesn't work for all phat models. It only works on SCPH-5xxxx units with the "dragon" mechacon. So far I remember, OP never said which model phat it is.
And MechaPWN is so far I know not regio free for PAL models.