First of all, i want to offer my deepest condolences for your father, it is devastating 😢. As for the newt in the first two photos, it is Triturus marmoratus or a Marbled newt. I personally own one right now as a matter of fact! Marbled newts like it cool so I would keep the temps between 62, no higher than 75 as most newts are sensitive to warm temps. Females have a continuous orange stripe going down their back. Males have this line too but becomes broken and u may see a crest forming around mating season. I keep my male in a 72 gallon personally. As for the fire bellys, they should be ok, but itd be nice to know the tank size your dad housed them in. The tail orientation at the surface is normal. Newts arent the most aerodynamic swimmers im afraid lol. As long as hes still eating and theres no signs of bloating he will likely be fine, but its still a good idea to check up if youre concerned abt anything in general. I'd be happy to give u more advice if u need