Your character concept has two specialties:
1. being mute
2. being a drow in disguise
1. Being mute is a big disadvantage for every player character, because the player must roleplay this in every session and the player character can not use the spech to communicate with other NPCs.
It is hard to play a mute PC in every session and I would not allow a mute PC in a long lasting campaign because I doubt that a player can play a mute PC good for a long time.
I would allow this concept only in a one-shot session or one longer adventure (max. 5 sessions).
If a bard can play a lute and sing at the same time he can use (or continue to to use) his bardic music and can also cast a spell.
A bard is a master of music and words (bluff, diplomacy). If you steal him his speech he can not take skills like bluff or diplomacy. If somebody has found out that the PC is a drow, the PC can not talk his way out. Without his speech the bard can not show his "goodness" easily.
This PC is limited to the traveling circus. He can not communicate with other persons. A traveling bard (a non-drow) raises no suspicions, but a lone clown in party of adventures raises suspicions.
2. Drow are LA +2 races, so your 1. level bard starts in a group of level 3 adventurers. A bard is also a spellcaster. So with the LA +2 your bard looses one level of spells. The bard gets his first first level spell in level two not like a wizard in level one. The bard also get some spells (e.g. charm monster) before a wizard gets them, so the saves against this bardic spells are lower than the saves for this spell as a wizard spell.
I think your concept is good for an interesting NPC.
Why do you use a bard as class ? because of the spells ? If you want a NPC musician (mime) you can take an expert with class levels in perform, balance, escape artist, disquise, jump, tumble, etc.