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We report deep spectroscopy of ten planetary nebulae (PNe) in the AndromedaGalaxy (M31) using the 10.4m GTC. Our targets reside in different regions ofM31, including halo streams and dwarf satellite M32, and kinematically deviatefrom the extended disk. The temperature-sensitive [O III] 4363 auroral line isobserved in all targets. For four PNe, the GTC spectra extend beyond 1 micron,enabling explicit detection of the [S III] 6312 and 9069,9531 lines and thusdetermination of the [S III] temperature. Abundance ratios are derived andgenerally consistent with AGB model predictions. Our PNe probably all evolvedfrom low-mass (<2 M_sun) stars, as analyzed with the most up-to-date post-AGBevolutionary models, and their main-sequence ages are mostly ~2-5 Gyr. Comparedto the underlying, smooth, metal-poor halo of M31, our targets are uniformlymetal-rich ([O/H]> -0.4), and seem to resemble the younger population in thestream. We thus speculate that our halo PNe formed in the Giant Stream'sprogenitor through extended star formation. Alternatively, they might haveformed from the same metal-rich gas as did the outer-disk PNe, but wasdisplaced into their present locations as a result of galactic interactions.These interpretations are, although speculative, qualitatively in line with thecurrent picture, as inferred from previous wide-field photometric surveys, thatM31's halo is the result of complex interactions and merger processes. Thebehavior of N/O of the combined sample of the outer-disk and ourhalo/substructure PNe signifies that hot bottom burning might actually occur at<3 M_sun, but careful assessment is needed.

Chemical Abundances of Planetary Nebulae in the Substructures of M31 -- II. The Extended Sample and A Comparison Study with the Outer-disk Group