1. Again, instancing. This has been put forward before and was told it'd be too much work at this current time. Also, I believe a point around factions was mentioned where it was said that "there won't be any faction specific areas" - this might extend to guilds, too.
2. That's a lot of work, not being funny but Admins don't have the time to take requests from several hundred guilds for their clothes, and it's down to the artists to design the clothes, not the admins. It's a good idea, but very, very flawed in the way this has been put forward.
Alternatively, you could just ask everyone in the guild to wear a specific set of clothing, but this has the issue of members only clothing and limited choice.
I would say try rethink number 2; think of a viable way you could implement this with minimal staff interference. Try find flaws in your own idea to make it better and explain alternatives, just putting forward a majorly vague idea is helping no-one if there's no thought process behind it.
I know it's a lot of work! That's why you either gonna make it expensive or just employ more graphic editors :)