I'm a bit confused by the bolded part of Stealth:
What happens when a character possessing draw a line to another character that passes by square of hindering terrain which is occupied by opposing character possessing stealth?

Normally the LoS would be blocked, but allows the attacker to ignore opposing characters for LoS purposes.

Does stealth block lines of sight draws through the stealthed characters, or does "to" mean that LoS is blocked only when the stealthed character is target?

Stealth only blocks LoF to that character when they are the target. Sharpshooters can target a character behind a Stealth'd character normally.

First of all, the term that you are looking for is "line of fire" here. There's no line of sight in this game.

Now, dairoka is correct, but I wanted to emphasize something. The LoF would normally be blocked through a Stealthed character, but it has absolutely nothing to do with the Stealth. It would be blocked by every character.

Which I noted in my initial post

Sorry about the LoF/LoS confusion.