I did the solo no reload challenge with a shadowdancer - it went well, admittedly *with* a little metagaming in places - due to primarily avoiding all fights except one v one, and in those backstab, hide, backstab is super powerful in BG1. (Still easily maxed out XP before hitting the maze leading to undercity.)
However, the one place that is a total crapshoot is the Duchal Palace fight, where all the nobles turn into dopplegangers and you expose sarevok as a bad dude.
The problem is that as a thief, your attack is too light / too many misses to damage quickly. Meanwhile, you need to take out a lot of dopplegangers in a hurry to prevent the 2 town leaders from dying; if they die, it's game over, so forget about backstabbing, even hasted.
The only way i could get it to work is to use algernon's cloak on lady jannath to charm her, then cast all her protections before belt makes his speech, and then dispel magic to remove the dopplegangers' haste. However, some fair percent of the time (maybe 25% - i re-tried the scene several times after success to confirm how often the charm works), she makes a saving throw, and then you're hosed because she's too slow to get her magic going, and won't use dispel.
I also can't see how a solo shadowdancer could succeed without metagaming, since that would also mean not getting lady jannath protected up pre-fight.