Finding Unsearchable Opponent Guild Information

Well, you can type basically any characters if you change the language settings of your device's keyboard. (if that keyboard app supports it, that is...) I just used my favourite/default keyboard app Swiftkey to input some Greek characters, for the same reason.
Apart from that (especially if the character set is so cryptic that you cannot identify the language), you might try to use something like Google goggles/Translator to read it from a screenshot and create a search from it.
But I don't know if it's worth THAT much effort. After all, knowing the opponent's overall strength doesn't really help you - you need to decide for each defending team whether you can beat them or not.

I'm just curious how we stacked up against the guild we just crushed. Seems like they should have dominated us entirely, but didn't.

The total enemy GP also doesn't mean that much as long as you don't know how many people really signed up and played really actively. A really interesting statistic would be the total GP activated in the beginning of the battle, and both the total GP of toons sent into battle (defense and offense) and enemy GP defeated (for each enemy toon killed). You would know you are performing better if your ratio of defated versus used GP is higher than that of the enemy guild...