Is 1/2" pipe adequate for supplies inside a home?

I have a small off-grid cabin with a shallow well of 22ft deep. Right next to the well, I will install a well pump (not sure which type yet) to pump water from the well to the home. The well is about 100ft from where the water will enter the home. Before entering the home, the water will go through a water filter, then split into hot and cold lines (hot line going into a tankless gas water heater). When lines enter the home, it immediately feeds a kitchen sink and washing machine. Then will T to a bathroom (4ft in distance from kitchen sink) to feed a shower head, bathroom sink, and toilet (with a bidet sprayer sharing the toilet inlet). Inside the house will be copper pipe. Line from well to home probably 1" PVC.

QUESTION: Will I be okay using 1/2" to feed everything inside the home? Or should I step up to 3/4" to all the fixtures? Will I have any issues with pressure? Will one size make the pump more energy efficient? And any advice on what type of pump to get would be greatly appreciated!

It's possible I switch to a gravity fed system in the future, another thing to keep in mind.

Half inch I.D. is fine to each fixture. It's what's used in modern homes. Almost no consuming device can use 3/4" throughput anyway--they all have valves or restrictors or supply lines that are much smaller. An exception would be for a local outdoor spigot. Those are usually still 3/4".

Use 3/4" where you need to serve multiple devices, then drop to 1/2" where you split.

It's not only ok, but preferable to use 1/2" line for hot water, since this reduces the volume of cold water wasted as you run the tap waiting for hot. 1/2" is adequate for cold as well. At any rate using 1/2" will save on piping material cost.

You can run 3/4" to the entry point of your structure and to the treatment system and water heater. This will ensure good flow. Then, make your in-structure short runs with 1/2".