10 neon tetras - you have more chance of success with these if you add them later when your tank is more 'mature'. General theory seems to be that 6 months should make a tank 'mature'.
3 glass catfish. These like to be in bigger groups and again they prefer the mature tank.
4 shrimp(not sure what type,prob cherry) No problem with these, as long as you dont have fish big enough to eat them.
ruby shark - dont think any 'shark' is suitable for 125L as they get quite big.
5 corydoras(not sure what type). These will be fine, but have 6 minimum as they prefer bigger groups.
blue betta - not a good idea. These are also called "Siamese Fighters" and are known for their aggression. Depends on the personality of the fish, some can be fine in a community, some can attack the other tankmates, especially if the tankmates are brightly coloured.
maybe a few platys or guppies. These should be fine. Try to keep a 2:1 female to male ratio to ease the male harrassment on the females. Be prepared for lots of fry if you dont keep an all male/female tank.