No oil in pasta water, it may coat the pasta then it cannot
absorb the yummy sauces when tossed with it.
Just salt
it.
You don't actually bake the pasta cooked in the oven, you just
broil it till the cheese melts. I would just cook pasta (undercook
by about 2 mins) and heat cream in a pan with salt, pepper and
nutmeg. Put the pasta on a baking dish, sprinkle with shredded
cheese of your choice, top with the cream, top with more cheese,
then bake for 5 min.