From BDAG Greek-English Lexicon:
ἀναδείκνυμι fut. ἀναδείξω LXX; 1 aor. ἀνέδειξα; pf. ἀναδέδειχα LXX. Pass.: fut. ἀναδειχθήσομαι; 1 aor. ἀνεδείχθην; perf. ptc. ἀναδεδειγμένος (all these pass. LXX) (Soph., Hdt. et al.; ins, LXX; TestJos 2:7; Philo, Sacr. Abel. 35; Joseph., Tat.) ‘show forth’.
1) ἀναδείκνυμι occurs only twice in the GNT, that's hardly enough evidence to make a firm decision on its potential relevance to Christology.
2) If you'll notice, each occurrence apparently has a different sense, one from the other. How it's used in Luke is not how the word is employed in Acts.
3) Let's say that Luke uses ἀναδείκνυμι to delineate Jesus' activity in his Synoptic Gospel. Does that mean he couldn't apply the word to the Father in Acts 1:24? That would be like saying that because God loves humankind and Jesus loves humankind, therefore Jesus must be God. Yet performing the same action does not necessarily place two entities on level footing as shown by the fact that Gabriel could love humankind too; however, that would not make Gabriel ontologically equal to Jehovah.
4) Jesus is clearly not the referent of Acts 15:8, but God is. It makes better sense to apply Acts 1:24 to the one clearly described as the knower of hearts by Luke. Moreover, see the prayer in Acts 4:24-31. The Father is addressed as "Sovereign Lord."