[DC 86]

I think I'd quibble with a few of your metrics here:

1)  First, you have Estrada and Duggar mixed up.  Estrada is the RHB, and Duggar is the LHB.  
2)  A RHB is two full steps further from first base, and his inertia post-swing is moving away from first base, whereas a lefty's inertia is moving toward's first base.  So I believe your 0.07 (7 hundredths of a second) is not quite accurate.  Two very fast switch hitters were between 0.4 and 0.45 seconds faster from the left side than the right (Mickey Mantle and Bo Jackson).  Mantle had the fastest time to first at 3.1 from the left and 3.5 from the right.  Bo Jackson was 3.2 from the left and 3.65 from the right.
3)  I checked Statcast's 90 foot sprint, and it shows Dugger (3.85), Slater (3.93) and Estrada (3.96).  This measures Slater as faster than Estrada.
4)  Tonight's announcer referred to Slater as the "fastest Giant."  Right before the first pitch in the 11th inning.

In other words, I'd take Estrada's speed, then Slater's speed over Duggar's speed...

Statcast Running Splits Leaderboard | baseballsavant.com (mlb.com)

1. You are correct that it's Estrada who is the RHB and Duggar the LHB, I acknowlege my mistake, although this doesn't change the fact that both are faster from home to first than Slater.

2. MLB uses a table for scouting players which roughly corresponds to aggregated Statcast data. Note that the LHB/RHB delta in home-to-first times is not static; data supports what is intuitively obvious, which is that the difference in times is less pronounced among faster players (as well as the converse being true for slower runners). 

For players in the 4.0 second range the delta is set at .024 seconds.
For players in the 4.2 second range the delta is set at .048 seconds.
For players in the 4.4 second range the delta is set at .072 seconds.
For players in the 4.6 second range the delta is set at .096 seconds.
For players in the 4.8 second range the delta is set at .120 seconds.

I know the information about Mantle's time has been widely published and frequently cited, but it's absurd to think that he ran to first in 3.1 seconds, with the caveat that perhaps the methodology used in the 1950s is different from current methods (similar to timing a 40 yard run with a rolling start and a stopwatch vs electronic timing from a standing start.) Different methodologies may also account for the notion that Mantle would be almost a half second slower when batting right handed; Statcast times every single batter to first base and the average difference between LHB and RHB is less than a tenth of a second.

3. Slater is indeed faster over a 90 foot distance than Estrada, just as Mike Yastrzemski is faster over a 45 foot distance than Slater. Different players excel over different distances, just as in T&F. "Fastest" refers to to whoever literally runs fastest, and that's Estrada now.

4. Announcers frequently say things that aren't accurate. Slater is certainly in the group of fastest Giants and it's a matter of fractions of a second either way. Saying that Slater is the fastest Giant isn't an outrageous statement, a lot worse things are said on the broadcasts.

[DC 86]

I think I'd quibble with a few of your metrics here:

1)  First, you have Estrada and Duggar mixed up.  Estrada is the RHB, and Duggar is the LHB.  
2)  A RHB is two full steps further from first base, and his inertia post-swing is moving away from first base, whereas a lefty's inertia is moving toward's first base.  So I believe your 0.07 (7 hundredths of a second) is not quite accurate.  Two very fast switch hitters were between 0.4 and 0.45 seconds faster from the left side than the right (Mickey Mantle and Bo Jackson).  Mantle had the fastest time to first at 3.1 from the left and 3.5 from the right.  Bo Jackson was 3.2 from the left and 3.65 from the right.
3)  I checked Statcast's 90 foot sprint, and it shows Dugger (3.85), Slater (3.93) and Estrada (3.96).  This measures Slater as faster than Estrada.
4)  Tonight's announcer referred to Slater as the "fastest Giant."  Right before the first pitch in the 11th inning.

In other words, I'd take Estrada's speed, then Slater's speed over Duggar's speed...

Statcast Running Splits Leaderboard | baseballsavant.com (mlb.com)

1. You are correct that it's Estrada who is the RHB and Duggar the LHB, I acknowlege my mistake, although this doesn't change the fact that both are faster from home to first than Slater.

2. MLB uses a table for scouting players which roughly corresponds to aggregated Statcast data. Note that the LHB/RHB delta in home-to-first times is not static; data supports what is intuitively obvious, which is that the difference in times is less pronounced among faster players (as well as the converse being true for slower runners). 

For players in the 4.0 second range the delta is set at .024 seconds.
For players in the 4.2 second range the delta is set at .048 seconds.
For players in the 4.4 second range the delta is set at .072 seconds.
For players in the 4.6 second range the delta is set at .096 seconds.
For players in the 4.8 second range the delta is set at .120 seconds.

I know the information about Mantle's time has been widely published and frequently cited, but it's absurd to think that he ran to first in 3.1 seconds, with the caveat that perhaps the methodology used in the 1950s is different from current methods (similar to timing a 40 yard run with a rolling start and a stopwatch vs electronic timing from a standing start.) Different methodologies may also account for the notion that Mantle would be almost a half second slower when batting right handed; Statcast times every single batter to first base and the average difference between LHB and RHB is less than a tenth of a second.

3. Slater is indeed faster over a 90 foot distance than Estrada, just as Mike Yastrzemski is faster over a 45 foot distance than Slater. Different players excel over different distances, just as in T&F. "Fastest" refers to to whoever literally runs fastest, and that's Estrada now.

4. Announcers frequently say things that aren't accurate. Slater is certainly in the group of fastest Giants and it's a matter of fractions of a second either way. Saying that Slater is the fastest Giant isn't an outrageous statement, a lot worse things are said on the broadcasts.