Persona games shouldn't be too hard to find. P3 Fes, P3P, and P4 are fairly abundant last I checked, P2: Innocent Sin just came out, and P1 PSP is a few years old but is on PSN if worse comes to worse. The only problematic ones are P1 PS1 and P2: Eternal Punishment, and most people prefer P3/P4 (and those are easier to get into anyway). Even if you DID want those, better to just play the PSP games, P1 on PSP is uncut and P2:IS came out before EP anyway.
As for Eternal Sonata... uhh, gameplay may be fun enough, but there's better options. And Shadow Hearts a fairly good series overall, but each game may be fairly pricey now.