Yeah - those 2e ninjas are especially, um, funky, I guess...
1e changed rangers and bards considerably, with both versions fairly interesting (but often one more powerful than the other)...
1e rangers were powerful warriors with 2d8 hp at 1st level (hard to kill) who did wallops of damage to giants and humanoids, could cast both druid and magic-user spells (druid spells were more combative in those days), and were trackers.
2e rangers were sort of nature scouts who had affinity with animals and could cast plant/animal spells and track.
1e bards were very difficult classes to join, but eventually were fighter/thieves who had druid spells, magical charm abilities, and so on, but had a very strict hierarchy.
2e bards were very interesting - sort of pseudo-thieves (or tinkers) with good fighting and general magic-user ability (as they used the thief XP tables, they got to higher levels quickly).
Some people like to keep all versions in their 1e/2e campaigns, but I guess one could rename these to make them work with each other...