I would say no due the lower swingweight the better, but when it howling they might get easier blown out of the water when you are swimming. I can imagine that the become more direct/precise because of less counter weight, but that is something you get used to.
Agree, no, not harder to foil. There are pros and cons around ultralight boards (and all elements of your foil system) if decide to go down that rabbit hole.
Yes. But it's like with everything in foiling - if you change the setup and/or conditions significantly, you may need to give it a few sessions before you'll get used to it. Take your very responsive 3.5 kg board and a nice 500+ cm2 foil with a small stabiliser first time into short period chaotic bigger waves and you'll find the setup rather difficult to use at first, but you'll get used to that quickly.
Take it out the car, put it on the ground, turn to the car to get the foil, turn back, see it rolling across the ground in the distance. Go and run after it
my 83L board is 4.3kg (KT custom sandwich). I don't feel any greater sensitivity in high winds, quite to the contrary, I find larger and heavier boards are more difficult to ride, more swing weight tends to create more movement which is more difficult to control. But maybe that's just me.
Slab said.. Take it out the car, put it on the ground, turn to the car to get the foil, turn back, see it rolling across the ground in the distance. Go and run after it
