The selection of suitable starter and probiotic cultures is a critical factor influencing the quality, functionality and consumer acceptability of fermented soy products. The present investigation was undertaken to evaluate the technological and probiotic characteristics of six selected cultures, namely Lactobacillus acidophilus NCDC15, Lacticaseibacillus casei NCDC17, Lacticaseibacillus rhamnosus NCDC24, Lactiplantibacillus plantarum NCDC25, Bifidobacterium bifidum NCDC232 and Streptococcus thermophilus NCDC293, with the objective of identifying suitable cultures for fermented soy yoghurt manufacture. The cultures were evaluated for growth characteristics, acidification behaviour, acetaldehyde production, exopolysaccharide (EPS) synthesis, bile tolerance and cholesterol assimilation. Significant differences (P≤0.05) were observed among cultures for all evaluated parameters. NCDC293 exhibited the highest technological performance with superior growth rate (0.278 h⁻¹), shortest generation time (2.49 h), highest titratable acidity (1.12%), acetaldehyde production (30.4 ppm) and EPS production (198.2 mg/L). NCDC25 demonstrated the highest probiotic potential, recording maximum bile tolerance (94.8%) and cholesterol assimilation (61.2%). NCDC24 exhibited balanced technological and probiotic characteristics and ranked third overall according to CTPI analysis. Comparative ranking based on the Composite Technological–Probiotic Index (CTPI) identified NCDC25, NCDC293 and NCDC24 as the three most promising cultures for fermented soy yoghurt manufacture. NCDC293 exhibited superior technological performance, whereas NCDC25 demonstrated the highest probiotic potential and the highest overall CTPI score. The results suggest that the combination of Streptococcus thermophilus NCDC293 and Lactiplantibacillus plantarum NCDC25 possesses considerable potential for the development of fermented soy yoghurt with improved technological and functional properties.