First time at endgame, need some guidance (Long post)

Hi
This is my first time got to level 93, I've done all of the T16 maps available (I only got 2 void stones) and a few Maven Invitations and I got to a point where I don't know what to do next. So I've prepared some questions, hopefully some veterans kind enough will answer them for me and show me the direction of what I should do next.
Right now I only have one quest available which is The Elder "defeat the memory of the elder in the shaper's realm". is this the Uber Elder everyone talks about? How do I get to him? Do I just keep doing the influence maps? By the way, what's the different between normal maps and those influenced by the Shaper and the Elder? Are they supposed to be harder and what's the point of doing them?
Enough about the Elder now it's Maven. So I keep letting Maven witnessed maps to get invitations? How will it play out? Do I get to fight Maven finally at some points?
I've done some The eater of the world and The searing exarch maps but don't know what's the point of doing them so I just let Maven witnesses maps instead. Do I need to do them?
Move on to map missions. I don't like delving so can I just leave Niko mission alone? I've done Einhar, Jun and Alva before to a point where I just stop doing them all at once and play with what come to map randomly. Is it ok or I need to do them all? I'm kinda at a point where I want to do a map quickly and don't want too much distraction.
Lastly is about currency, I managed to got one exalted orb dropped from a blight cache and a few hundred chaos (I did so many chaos vendor recipes). I'm playing skeleton mage build and I invested about 3 ex on it. Now I don't know how to get more exalted to improve my build. I used some guide on atlas to focus on Harbinger and Abyss by the way. I'm really not sure what's the different among all of the options so I just pick one.
So I just keep chisel + alc + vaal T16 maps and hope for drops? I have some scarabs but don't know how to find more. I still don't fully understand how ppl "juice" maps to a point where exalted and valuable items drop more often.
I think this will be all for now, hopefully it's not too long for you guys. Please help me, I really appreciate it. Thanks alot. Peace.

Uber Elder:
Kill Shaper and normal Elder. Both will drop fragements allowing access to Uber Elder.
To get access tp Shaper/Elder, you need to kill their GUardians. Those will drop fragments giving you access to Shaper/Elder which will drop Uber Elder fragments when you kill them.
Its wuite a grind to get there.


Maven:
Do her invitations. You will drop Maven Cresecent fragments. 10 of those are needed to turn those into a Mavens Writ, which you put in your map device to fight her.


Currency:
You dont srop exalted orbs. I mean they do drop but thats not the way to get huge amounts of those.
You buy them for your chaos orbs and you sell everything else you dont need (like scrabs or whatever it is) for chaos orbs.
This way you can convert stuff you dont need into chaos and then into exalts.