What is the maximum number of drinks that might be taken in one play
of the St Valentine's Day Massacre in Alcoholic Family Business?

The only cards that can grow the hit list faster than a mob war can
shrink it are the Double Contracts, Double Cross, and Vendetta. In my
set there are three Double Contracts. In the absolute worst case you
might have a reshuffle at exactly the right time, so we can use all
these cards (except St Val's) twice in a row.

Let the players be Alice, Bob, Charlie, Derek, Eddie, and Freddie,
with their lobsters being A1...A9, B1...B9, etc., with A3d indicating
Alice's third lobster put on the hit list by Derek, usw. Freddie will
play the St. Val's. The final play will be Double Cross, Double
Contract (x3), Vendetta, Mob War/Truce (gets it back to single-rate
mob war), Double Cross, Double Contract (x3), Vendetta, St
Val's. We'll get as many of Freddie's lobsters on the hitlist as
possible.

We start with a hitlist of 5 lobsters, X1...X5 (we don't know whose
they are yet). Alice plays Double-Cross and a lobster is shot:
X2 X3 X4 X5 B1a C1a D1a E1a F1a

Bob plays Double Contract on Alice (saving Freddie's lobsters for later)
X3 X4 X5 B1a C1a D1a E1a F1a A1b A2b

Charlie plays Double Contract, Bob:
X4 X5 B1a C1a D1a E1a F1a A1b A2b B2c B3c

Derek plays Double Contract, Charlie:
X5 B1a C1a D1a E1a F1a A1b A2b B2c B3c C2d C3d

Eddie plays Vendetta, starting double-rate Mob War:
C1a D1a E1a F1a A1b A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e

Freddie plays Mob War or Truce, taking us back to single-rate:
D1a E1a F1a A1b A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e

Alice plays her second Double-Cross:
E1a F1a A1b A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a

Bob plays a Double Contract on Eddie:
F1a A1b A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a E3b E4b

Charlie plays a Double Contract on Eddie:
A1b A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a E3b E4b E5c E6c

Derek plays a Double Contract on Freddie:
A2b B2c B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a E3b E4b E5c E6c F5d F6d

Eddie plays Vendetta: 
B3c C2d C3d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a E3b E4b E5c E6c F5d F6d A5e A6e B7e B8e C7e C8e D5e D6e F7e F8e

Freddie plays St. Val's:

There are 34 lobsters on the hit list, so we'd better get a total of
102 drinks.

However, we can slightly improve matters for Eddie. C2d and C3d, put
on the hitlist by Derek's first Double Contract, could instead be E7d
and E8d.
B3c E7d E8d A3e A4e B4e B5e C4e C5e D2e D3e F2e F3e B6a C6a D4a E2a F4a E3b E4b E5c E6c F5d F6d A5e A6e B7e B8e C7e C8e D5e D6e F7e F8e

We can't increase the number of lobsters any further (no more cards
that extend the hitlist faster than the death rate) and we can't get
more than 8 of Eddie or Freddie's lobsters on (a Double Contract or
Vendetta would have to be used on only a single lobster).

Alice takes 9 drinks, 4 for A3-A6, 5 for counters.
Bob takes 8 drinks, 6 for B3-B8, 2 for counters.
Charlie takes 8 drinks, 5 for C4-C8, 3 for counters.
Derek takes 9 drinks, 5 for D2-D6, 4 for counters.
Eddie takes 27 drinks, 7 for E2-E8, 20 for counters.
Freddie takes 41 drinks, 34 for lobsters on the list, 7 for F2-F8.

That's a total of 102. The survivors would be A7/8/9, B9, C2/3/9,
D7/8/9, E9, F9... but we started with 5 lobsters on the list, so at
most 7 of those 12 lobsters can survive... we're not necessarily in
automatic Mob War.