There is no difference between DCC for HO and O scale.
There is a difference in the amperage ratings required for some locos vs others. Many older O scale locos require more than one amp to run and pull a load. Some old Max Grey brass may require as much 3-4 amps.
So there is a difTference between what is needed based on what you plan to run. You should test the locos you want to run to find out what the typical amp draw is and what the amp draw is at stall. Then look at the amperage ratings for the decoders you have to see what they can handle. If the decoder is rated for more amps than the loco draws it will work fine. If not, you burn out components.
Now similar logic applies to the command station too. You need to add up how many locos you plan tun at one time how much current (amps) they will draw plus how much lights and such in passenger cars draw. Then look at the rating on your command station. If the total amps you plan to use are less than the rating of the command station, you can use it. If not, you need a higher rated one.
Most large layouts use more than one "booster" They ;use one command station and then add boosters as the layout grows and the amperage needed gets too large for just the command station alone.
Any command station you have ought to run any single O scale loco. And most new ones draw less than an amp, so a 5 amp station ought to handle 5 at one time but 3-4 might be safer to avoid over heating of the internal circuit breaker going out.
Any throttle that works with you system will work in O scale or any scale. The throttle just tells the command station what signal to send to the decoder in the loco. It carries no voltage or current for the loco.
I have many decoders rated at 1.5 amps continuous and 2 amps stall in smaller and/or newer O scale locos. These are so-called HO decoders. But it is all about the amp rating needed.