Hotstart is when the amber light on the ITT indicator comes on(815°).
During an engine start with ITT above 200° you should give fuel at 20%Nh
instead of 12% with cold engine.
The fuel/oil heater/cooler has nothing to do with the ITT during startup.
Bleeds are normaly in off,but i don`t think it will make a difference because the bleed valves are springloaded closed and a certain pressure is needed to open them.On 72 and 42-500 the MFC has a time delay to open function to keep the bleed valves closed for some seconds after engine start.The drop of ITT on the first seconds was explained earlier.The drop in ITT after lightup and the second peak are related to the opening of the
secondary fuel nozzles.
Normal reasons for a hotstart are:fingertrouble,EEC u/s,bat start,tail wind,
propbrake on,worn fuel nozzles,GPU cut out.