1) what's up with dues requirements and why? Guessing there's a cost to maintain a guild trader? Raffles?
-Certain guilds have a cost associated with them. Some require gold, some require a certain amount of activity, some require that you recruit a certain number of people to the guild. This might be per day, per week, per month - you get the picture. This is almost always to benefit the guild in some way - it's not just pocketed by those in charge. Requiring activity makes sure the guild stays active, requiring recruiting keeps the guild full, and requiring dues is usually for a guild trader or supplies for the guild - or recently, guild housing. There are other ways to keep a guild trader funded, like raffles or betting, but each guild decides how they do things themselves. Many guilds do not require anything at all, so as usual, to each their own.
2) what about guilds without a guild trader? Can you still trade within the guild somehow if there's no official trader located somewhere?
-One can always trade to other members within their own guild using a guild store as long as they have the requisite number of members. All a guild trader does is allow people outside the guild to trade using that guild store. One can always trade player to player regardless of guild status, so if need be one could always ask someone in a guild to buy something from their guild store and then trade them for it. To answer the first part, a guild is a lot of things without a guild trader. It is a community easy to group with, an easy way to fast travel without using wayshrines, and access to a guild bank, just to name a few things.
3) is it rude to join a guild with no intent to use voice chat? In deal with the public all day long and just want silence by the time my wife and kids are in bed.
-Some guilds might use voice chat, some might use text chat, some use both, some use xbox party chat, and some don't chat. It all depends on the guild. My general advice is to find a guild that fits you, or at the very least, speak with guild admins. In my experience most will understand not wanting to use a mic when you have a lot of things going on in the background.
4) is it reasonable to assume using a keyboard to chat in game is acceptable for a guild? I have a wireless keyboard for Xbox one if so.
-It is, in fact, a thing that is in the game, so it is, by definition, allowable. That said, as before, every guild is different. Some prefer voice chat and won't pay attention to text chat.
5) so you can join up to 5 different guilds? Why would one want to do that? I'm feeling overwhelmed by idea of being in one guild much less five.
-Yes, you can join up to five different guilds at any one time, per account. The key phrase is "up to". You needn't join ANY if you don't want to. Some who do might have several different reasons. You might want to load up on trading guilds, like Articulemort, so you can be a master trader, make a lot of money. You might want to have one main social guild, and the rest can be for trading. You might want to have three different guilds for PVP, one for each alliance as you switch characters in different alliances. There are plenty of reasons to join 5 guilds, but I would recommend sticking to just a couple active ones at a time.
6) I've experienced "end game" raiding guilds in both Everquest and World of Warcraft so I'm not unfamiliar with guilds, but how does an ESO guild relate to those experiences (assuming there are others who have done the same)? I remember how hardcore it was back in the day with officers chastising people for greeting newly logged in people because it interfered with guild chat during raids etc. I don't really want to relive those sort of experiences and just want to chill. Back then I was all about being on the cutting edge of new content but those days are long since passed for me.
-This is a fairly common thing, if you're looking for endgame guilds. Like before though, every guild is different, so you'll have to look at their setup on an individual basis. And remember, you can have more than one guild too, so if you choose to join a guild like you described, it doesn't have to be the only one you're in.
7) is it a reasonable expectation to expect to be able to log in and play without having to join a group etc without feeling guilty about going solo mostly?
-A guild is there for you, when you need it. You should not go into guild shopping thinking that it's something you HAVE to do. So you should never feel guilty if you want to play your own way. Now, that said, like before, some guilds have certain requirements saying that to stay in the guild or keep a certain rank you have to help with groups or be active at least so much. If you don't want that, you may want to stay away from those types of guilds.
8) what are the "pluses" of being a part of an ESO guild? How about the "minuses"?
-The only real downside of being in a guild is that it takes up a guild slot another guild could be in, and maybe that you'll have some text chat in the corner of your screen you don't want, if you care about that sort of thing. The benefits of being in a guild - well I'll name off a few and see where I stop: In active guilds you can use "travel to player" to get a free teleport to a wayshrine, you have a guild bank that expands your inventory space and gives you free stuff, depending on how the guild uses it, you have a guild store which has many trading benefits I won't bother listing here, your guild might have a master crafter that can craft armor, weapons, and/or consumables for you, you have a community to be social with, you have access to many people's houses, you have a powerful grouping tool in a guild, and you get a sweet tabard. That's just everything I can think of right now at least.