The Standard Array for D&D 5e is 15, 14, 13, 12, 10, 8. This is 27 points using point buy and all the companions so far use this array to generate their ability scores.
Str: 14 = 14 (7 pts)
Dex: 9 = 8 (0 pts) +1
Con: 13 = 13 (5 pts)
Int: 10 = 10 (2 pts)
Wis: 16 = 15 (9 pts) +1
Cha: 14 = 12 (4 pts) +2
9 + 7 + 5 + 4 + 2 + 0 = 27. Shadowheart has no more points to spare.
Could her ability scores be better? Sure. Swapping the 8 in Dex for the 12 from Cha and moving the racial bonus point from Dex into Con would give
Str 14
Dex 12
Con 14
Int 10
Wis 16
Cha 10
She would be less charming but more agile, have a higher AC and more hit points. The Dex and Str could be swapped for a Finesse build, but this would require her to be proficient in at least short swords or rapiers.
