If I were to discard Orphan of the Greenblood as an any phase action to cause a character to lose it's icons after the character kneels to attack, does that character a) remain in the challenge even though it has no icons? b) Count its strength? It'd be nice to be able to get a character to kneel before rendering them useless with this card but not sure if I have the mechanics correct. I'm leaning towards they def don't count str but not sure if they are removed since they are no longer qualified to participate...

First entry in the actual FAQ section of the FAQ:

If my character loses a military icon in the middle of a military challenge, is that character removed from the challenge?

No. Once a character is in a challenge, it can only be removed from that challenge by an effect that specifically removes the character from a challenge, an effect that removes the character from play, or by an effect that changes control of that character. Gaining or losing icons mid-challenge does not affect the attacking or defending status of that character.

Since the character is not removed from the challenge, it will of course count its strength.

Specifically, look again at the way the rules talk about participation in challenges:

1. In order to be declared as an attacker, a character must be standing and have the right icon. (Declaring it makes it a participating character in the challenge on the attacking side.)
2. In order to be declared as an defender, a character must be standing and have the right icon. (Declaring it makes it a participating character in the challenge on the defending side.)
3. When you resolve the challenge, you count the STR of all participating attackers and defenders, then compare.

Note that there is nothing in the instructions for resolving a challenge about having the right icon. The game only cares what icons a character has when getting a character into a challenge. Once it, that's it until something specifically removes it from the challenge (or from play). Icon status is meaningless - or at least a non-factor - when determining the winner of the challenge.