Urban Arcana isn't needed, really, but would probably help with what you're going for. UA is a hardcover book similar in thickness to D20M, and adds material for making a D20 Modern campaign somewhat more like D&D. The setting's default assumption is that the Plane of Shadow is bleeding over into the Material Plane that Earth is located on, as it occasionally overlaps partially with Earth every few centuries (or something like that). However, the book is more rules material than setting material, I think.
You can find most of the rules from Urban Arcana in the D20 Modern System Reference Document (called the Modern SRD or MSRD on the website), at the Wizards of the Coast website. This is free, but may be lacking a few tidbits from the book (and of course, lacks pretty much all of the setting-specific descriptive material from the book).
The D20 Cyberscape book (softcover and much thinner than UA), also from WotC, could help with the Final Fantasy 7 feel in some regards, though it's not nearly as useful in that regard, since it's mostly about cybernetics, the VR-Net, and the HI-Net. Cyberscape has a chapter on using cybernetics in non-modern settings, as Golemtech mainly (called such due to the resemblance between the grafts/implants and golem pieces). This chapter includes rules for Bone Runes, Necrotics (grafting undead body parts and humours/fluids to living creatures), and some pieces of wetware (living biological grafts or genetic alterations, such as stronger pheremones, telekinetic brain developments, claws, gills, etc.). I think some or most of Cyberscape is also available for free at the Wizards of the Coast website, as a D20 Future web enhancement or as part of the D20 Modern/Future SRD.
I'm sorta tempted to suggest you use Shadowrun (a decidedly non-D20 game) 3rd Edition or 4th Edition to run a Final Fantasy 7-esque campaign..... I think with a few tweaks, removing a few items and pieces of cyberware, weakening some guns (since FF7 assumes a level of tech similar to modern or industrial-revolution, whereas Shadowrun is near-future based), and improving the melee combat rules (which are purposely weaker and simpler than the ranged weapon rules, since Shadowrun has so many guns and spell-flinging magicians around), it could be fairly well-suited to the campaign. YMMV, of course.
Spycraft (a D20 System game that's sort of an alternative to D20 Modern, produced by a different company) is also a very effective option I think, but I don't know whether or not it's still in print.... I think the 2nd Edition was most recent. I don't, however, think there was any magic rules available for Spycraft, so you'd likely have to take such rules from a different source.
