the OTP does not belong to starhub. it belongs to NLT.
is your OTP going to be in the original location as when it was first installed? when opennet (previous name of NLT) ran cables for landed houses, the termination point is somewhere inside the house as opposed to for new built where the termination point will be inside the meter compartment. I believe you could get NLT to relocate the termination point for you and if they are shifting it to the meter compartment then you would need to get your contractor to run a new fiber from the meter compartment to wherever you want the internal termination point to be.
Of cos you can just leave the OTP where it is now like you mentioned along with the ONT, then run a Cat6 cable to wherever you want to install the other switches and equipment.
Is the DB inside your house? If yes, does it have space to store network equipment and such? Honestly speaking, the location of where the network points will terminate should be decided very early on in the project rather then being left as an afterthought since you will have problems trying to run cables or have to redo finishing just to run the cables. I'm not sure how many network points you are planning to have but assuming you are going to have 2 points for each bedroom and 2 for living room, that will be a total of 14 points for 6 bedrooms and the living room. Adding on to your 6 POE CCTV points you are looking at at least 20 Cat6 cables. I can tell you that trying to hide 20 Cat6 cables is not going to be easy and if you are planning to have the termination point in your living room, then you will need to find a way to hide the big ugly trunking for the Cat6 cables. For my house, I am using those big trunking for aircon pipes to house my network cables before they go inside my server rack.
And don't be so overly concerned about having no fan or heat issues. Like I mentioned, your roof attic is unlikely going to heat up to temperatures like 60 or 70 degrees so even if the equipment runs at around 40 degrees Celsius will still be ok. Equipment and hard drives for NVR don't last forever so you will need to replace them eventually