Most modern houses are built internally out of timber with only the outer leaf being built from brick. (And that is pretty much only for cosmetic reasons, the internal timber structure is perfectly capable of supporting itself on its own, an additional weatherproof external timber leaf would work just fine but unlike the US, is not considered acceptable by UK buyers)
Timber moves, shrinks, expands, flexes, and so on.
Plasterboard does not, You will inevitably end up with cracks where adjacent sheets of plasterboard but up against one another.
I cant really see any of those lionear cracks being a problem.
I would only be concerned about the cracks around the windows and doors if the internal walls are made from masonry. If they are timber leaf/plasterboard too, then there is no problem.
