The short answer to both questions would be YES. Also, the Boxcar had really abysmal single engine performance immediately after take-off. Here’s a page from the C-119G pilot’s manual:
654A4EB2-5B23-4DD9-9B70-524A039B09BC by
tanker622001, on Flickr
And from the C-119B manual
E3258071-0685-45B4-887C-9BCFF958B7BE by
tanker622001, on Flickr
When I was flying a B-17 out of Porterville we used to claim that the only reason that the jet was used on take-off in the Boxcar was to act as a glorified fuel dump to help it get off the ground. J-34 jet engines are relatively primitive and (as with all jets) the thrust at low air speeds is not very spectacular compared to that at say 400 knots. Any time that the Boxcar had a load of any significance the jet would be used both to improve take-off performance and to make the first minute or two of a piston engine failure considerably less fatal.
During the Fish Haul we had 115/145 avgas supplied for our use and the Boxcars had ADI available and used water injection on heavy take-offs. Here’s N3003 taking off from Egegik Beach southwest of King Salmon on one of the very few good weather days during the 1981 Fish Haul.
944C8698-F3D5-41C1-AC05-C71966CA0979 by
tanker622001, on Flickr
In all fairness to the Box, the P-2s also used both jets on every loaded take-off and water injection when it was available. After about 1990 ADI saw much less use in P-2s. Sis-Q Flying Service flew DC-6B’s for several years on contracts requiring carrying 3000 gallons of fire retardant. That was pretty iffy on a hot day and they used water injection all the time. The saving grace with tankers being that the retardant load could be dropped in a few seconds if a failure occurred during or shortly after take-off. That made the Go-No Go decisions a lot less stressful.
I once saw one of Sis-Q’s mechanics filling up a 5 gallon ADI can from a garden hose at La Grande. He said not to worry because the methanol was just to prevent freezing. When TBM Inc. first got C-123K’s one of the mechs mixed up ADI in a 10 gallon crock using water, methanol and a dash of oil (corrosion protection) from a recipe in the maintenance manual. It reminded me of my dad brewing beer in the basement when I was a kid.