Tifa reissue from what I can tell, they fixed the misassembled "cuffs" of her gloves, also just recently I noticed one fringe of her bangs is slightly different compared to first release as its reissue is maybe shorter and pointing to the other side and its giving Tifa reissue a different look
pic related is first release taken from this review:
https://lameazoid.com/bringarts-final-fantasy-vii-tifa-lockhart/compare that to pics above I posted which are reissue Tifas and you will see, its not much but I prefer 1st reissue for Tifa as its closer to the promo pics used in the box
For Aerith reissue, so far I haven't seen any difference, thought reissue's bolero before has thicker panel lines compared to 1st release but saw other's copies of reissue having none of that, but SE did fix her face plate being easy to dislodge/loose for the reissue
