I continued counting, from the last of the tables containing facts...
Boston|78|150|192||399|207||148| 294 | 146 || 80| 8|| 25 | 53
Player|GP|+/-|Tot||TGF|TGA||ES | ESF | ESA ||PPF|PPA||SHF |SHA
Orr |78|124|173||258| 85|| |154-179|47-55|| 79|0-8||0-25| 30
Green |78| 37| 26||125| 99|| | 99-124|79-87|| 1|0-8||0-25| 12
Awrey |74| 40| 29||116| 87|| | 89-114|66-74|| 2|0-8||0-25| 13
Dallas|73| 94| 70||154| 84|| |125-150|48-56|| 4|0-8||0-25| 28
Rick |67| 30| 15|| 63| 48|| | 28- 63|25-33|| 0|0-8||0-25| 15
Since Orr seemed to play basically nonstop in PP, we may assume his PP +/- is 79-8.
We may also think that other defensemen basically didn't play PP.
Boston|78|150|192||399|207||148| 294 |146|| 80| 8|| 25 | 53
Player|GP|+/-|Tot||TGF|TGA||ES | ESF |ESA||PPF|PPA||SHF |SHA
Orr |78|124|173||258| 85|| |154-179| 47|| 79| 8||0-25| 30
Green |78| 37| 26||125| 99|| | 99-124| 87|| 1| 0||0-25| 12
Awrey |74| 40| 29||116| 87|| | 89-114| 74|| 2| 0||0-25| 13
Dallas|73| 94| 70||154| 84|| |125-150| 56|| 4| 0||0-25| 28
Rick |67| 30| 15|| 63| 48|| | 28- 63| 33|| 0| 0||0-25| 15
Adding ESF for all defensemen gives 299. On the other hand 146*2=292.
These two sums doesn't have to be equal. For example penalized players jump into the play.
If one assume a PK unit of 2 defensemen and 2 forwards, it's not unlikely the penalized player being a defenseman too.
For example, Orr himself had 91 penalty mins.
Btw, if looking at penalty minutes, one should consider that a penalty doesn't necessarily give the opposing team a PP. Often one from each team may get penalized, etc.
We also know from hockey-reference.com, that Orr scored 3 SH goals, while Dallas scored 2. So Orr was on the ice for at least 3, probably far more, SH goals.
Boston|78|150|192||399|207||148| 294 |146|| 80| 8|| 25 | 53
Player|GP|+/-|Tot||TGF|TGA||ES | ESF |ESA||PPF|PPA||SHF |SHA
Orr |78|124|173||258| 85|| |154-176| 47|| 79| 8||3-25| 30
Green |78| 37| 26||125| 99|| | 99-124| 87|| 1| 0||0-25| 12
Awrey |74| 40| 29||116| 87|| | 89-114| 74|| 2| 0||0-25| 13
Dallas|73| 94| 70||154| 84|| |125-148| 56|| 4| 0||2-25| 28
Rick |67| 30| 15|| 63| 48|| | 28- 63| 33|| 0| 0||0-25| 15
We know that forwards Westfall, Marcotte, Sandersen and Esposito scored 7+6+6+1 = 20 SH goals.
But we have no idea which defensemen was on the ice.
Orr and Dallas seems to have been in for the most goals against on SH.
I am tempted to make guesses, assuming a pair of defensemen usually played SH.
Boston|78|150|192||399|207||148| 294 |146|| 80| 8|| 25 | 53
Player|GP|+/-|Tot||TGF|TGA||ES | ESF |ESA||PPF|PPA||SHF |SHA
Orr |78|124|173||258| 85|| |154-164| 47|| 79| 8||15-25| 30
Green |78| 37| 26||125| 99|| | 99-112| 87|| 1| 0||0-12 | 12
Awrey |74| 40| 29||116| 87|| | 89-102| 74|| 2| 0||0-12 | 13
Dallas|73| 94| 70||154| 84|| |125-135| 56|| 4| 0||15-25| 28
Rick |67| 30| 15|| 63| 48|| | 28- 51| 33|| 0| 0||0-12 | 15
Fine tuned guesses:
Boston|78|150|192||399|207||148|294|146|| 80| 8|| 25| 53
Player|GP|+/-|Tot||TGF|TGA||ES |ESF|ESA||PPF|PPA||SHF|SHA
Orr |78|124|173||258| 85||113|160| 47|| 79| 8|| 19| 30
Green |78| 37| 26||125| 99|| 32|119| 87|| 1| 0|| 5| 12
Awrey |74| 40| 29||116| 87|| 35|109| 74|| 2| 0|| 5| 13
Dallas|73| 94| 70||154| 84|| 78|134| 56|| 4| 0|| 16| 28
Rick |67| 30| 15|| 63| 48|| 25| 58| 33|| 0| 0|| 5| 15
These above guesses are of course questionable.
For example, it seems Orr wasn't on the ice for as many ES goals forward as one would expect, when comparing him to his teammates.
According to the guess, Orr was on the ice for 160 out of 294 ES goals forward, that's only .5442. That corresponds to 25 mins.
But did the team tend to score more in ES with Orr on ice, than without him. Probably. But on the other hand, Orr may have played more versus strong opposition, while his teammates may have played more versus weak opposition. Against weak competition, Esposito and the other guys may still, if they played, have helped the other defensemen stats.
So I choose to guess he played about 50 % of the ES time. That would mean 23 mins.
ES 23, PP 6, SH 5, Total 34.