Hydrogen as such can't replace fossil fuels as it needs to be produced first using energy.
It is only a vector. So many people make the confusion thinking that hydrogen is the solution.
And once a critical mass is reached, along with electrification of transportation, we can drastically reduce oil usage.
Systems and procedures for LNG can probably be adapted for LH2 with not too much difficulty, but ammonia will be the more practical choice, most places.
When it comes to Hydrogen, its basically industrial compressors, tanks, piping, etc.