Hardiplank siding paints up real nice. Make sure all caulking is complete. Make sure all cut ends are primed where possible. Good installers prime every cut before installing. No need to prime siding as hardiplank comes preprimed. Flat tends to look the best when new but will get dirty quickly. Satin is your best overall choice. Have them put on 2 coats for a paint job that will last a long time. I wouldn't put too much stock in the 'lifetime' claim. That is based on the average homeowner only staying in a particular house for 7 years. I have been using Duration since it came out, no complaints yet.

LOL Ok depends on the house. In my alaska home I want reflective quality in the winter, so most straight painted walls and ceilings are in semi-gloss (shock and horror and yet it looks wonderful). Some walls are finished with varnish or shellac (even more shock and horror but they are the walls ya'll always compliment LOL) and others have a metallic finish. A few are finished with paste wax which when burnished is pretty glossy. Only my very deepest wall color in the basement is done in eggshell and that's because it gets too much light and was dang near glowing heh heh I'm also old fashioned so all trim is done in the highest gloss possible and I love that look. Now in the victorian, flat, matte whatever you call it for walls, though the ceilings will be in metallics most likely on the main floor. Trim paint is mostly being removed but the interim trim paint will be high gloss paint. I had a high gloss and then lacquered finish wall in one of my townhouses a few years ago. It was for art and it was stunning. The other walls in the room had to be semi so they didn't scream "different sheen" next to that long wall.

There's lots of info on this page, linked below, including this - "Most ceiling paints have a flat finish, often the very flattest finish that the paint manufacturer produces. Any kind of glossiness, even the slight eggshell or satin sheen, shows up on ceilings. But as another attention-getting device, ceilings are sometimes painted in high-gloss sheens.Sep 25, 2019" Painting ceilings

I have no idea what brands are available to you but usually semi gloss is my choice with the same color in a matte for the walls. I think high gloss works in a very contemporary space but that would be hard to say without seeing your space. I have not dealt with a paint company that only makes one sheen so maybe share a bit more info.