Are thieves *required* in any of the gold box games? That is, the four Forgotten Realms games, the three Dragonlance games, and the two Savage Empire games.

Is having a thief recommended in any of them?

For Menzoberranzan, Ravenloft: Strahd's Possession, and Ravenloft: Stone Prophet, thieves are absolutely useless.
I don't even understand why there are lockpicks in the game; they always fail/break, and every lock has a key.

Fighter/Thieves are very useful for their backstab ability, especially in Curse of Azure Bonds and Death Knights of Krynn.
Single class Thief is one of the most useless classes, since the lock picking and such is so under utilized.

You can play all those games without a thief very well.

IIRC a pure Thief (and a Knight) is required for Champions of Krynn, but I don’t believe that is the case for its sequels.

Thieves are unfortunately not catered to in general in the Gold Box games. The engine does support the usage of thief abilities, but the designers rarely provide scenarios where the player can use them.

The games are very combat focused, and pure Thief characters are weak in that scenario. Backstab can be very powerful on a Fighter/Thief, but demihuman level caps are an issue.

the good things of thieves is they have the lowest xp requirements so they are the classes that lvl up the fastest.But i find it strange they cant use bows in pool of radiance.

Make them Elf Fighter/Thief or Fighter/Thief/Mage, and they can use Longbows with the Elves' +1 THAC0 bonus.
Never use single class thieves.

Yeah i notice a full thief isnt very useful, the funniest thing the character that does the most kills is my fighter/mage with a short bow sometimes even shooting twice, mostly i let my front fighters guard and let the enemies come to them getting free reactions, and i noticed lvling up goes very slow having to travel a lot betwean the slums and the resting place that ask 1 plat for the night, i hope that my resources wont dry up/ since most gear are only worth 1 gp

Don't worry, you'll be swimming in gold eventually. And the low level caps benefit multi-classed characters, while a single class will hit the roof too soon.

Are those trolss ogres part of the slum quest? I hope not.

They are, but you don't need to do the quests in order so I'd recommend saving that battle until your characters are at least level 3.

Thanks, well gonna need to get lvl 2 first because im still 1, but that orc encounter at their home is hard as well, they hit really hard.