All I can do is post about my Karvan that came with the winter package. You can see the hoses are insulated and their are membrane heaters on the side of both tanks.
As far as diesel, that's beenn around the US a long time. Sprinter Vans use them as do Some RVs
My friends with other Kimberleys have them and have no complaints
I have a karavan so I heat the compartment up at once, but since the toilet is across from the stove top, I can turn them on
I just installed the diesel heater. I had been using the hot water air heater from the factory that sucked. I should have upgraded then. Since it runs of the diesel hot water It ran all night and never smelled diesel inside. The hot water heater was noisy
In my test of my newly installed D2L Espar Diesel heater, it runs much quieter
I will be in Moab this week I will get a chance to try it with low 40's. I don't have a lot of experience with sub freezing temperatures, so cant really comment on how well the weather gear works. I know Brad Garland did and he added some insulation on one section of hose and was happy, but that again is a Karavan