Not an X-Chart expert but those are outs that were NOT converted. Not 100% certain if it means a hit.
Yeah, some are "Error On Foul Popup" which does not end up as an out, but not a hit either (simply, the hitter has another chance). Of course, giving an extra chance in a 150M environment costs more than in a low scoring environment. At 6 runs per game per team, each missed out costs 0.22 runs.
Here is my best guess :
Beckwith is 33 out of 54 X-opportunities:
(10 errors)
* 7 one-base error (perhaps one was 2-based error, perhaps one single plus one-based error)= 7*0.40 = 2.8 runs
* 3 dropped fouled balls: 3 * 0.22 runs = 0.7 runs
(9 other miscues)
* 2 singles: 2*0.47 runs = 0.9 runs
* 6 passed balls : 6 pb * 0.30 = 1.8 runs
* 1 wild pitch: 1 wp * 0.30 = 0.3 run
* 33 outs: 33 * 0.11 = -(3.6) runs
X-chart review: 4.9 runs
11 extra passed balls: 11*0.3 = 3.3 runs
18 throws in the field: 18 * 0.3 = 5.4 runs
3.3 + 5.4 = 8.7 runs
With regards to stolen bases, since your overall rotation has roughly a zero hold, I would assume that a -2 arm would allow 60 sb 30 cs. With this comparison, given that, under Beckwith watch, the team had 130 sb 40 cs, so:
70 sb: 70*0.25= 17.5 runs
10 cs: 10*0.5 = -5 runs
17.5 - 5 = 12.5 runs
Overall: 4.9 + 8.7 + 12.5 = 26.1 runs allowed compared to a 1e0(-2).
What we don't know is how Beckwith's 5-range affects the game with regards to the CATCHER BLOCKING plate rule. SOM management said a few times back in the days that the Blocking plate rule does apply in 20XX, but I always had doubts that it did. In any case, my doubts are even greater with ATG: I don't have any sign that that it does apply. If the rule were to be followed, Beckwith's defense would cost your team 20 runs only with consequences of allowing runners to score.
If the blocking rule doesn't apply, I would say, based on his offensive performance (96.4 runs created), he managed pretty good with a overall 70.3 positive runs, or 7.0 WAR. Not too bad after 129 games, for a projected 8.8 WAR for a whole season.
At 50.3 runs though, if the blocking rule applies, Beckwith would not be a good buy.