First off, welcome to CF. To answer your questions, as far as I know there isn’t anything beyond dikuclans and dioxides. If By off limit information you mean wand locations and the like, you do not necessarily need those to be competitive, especially at low level.
If you want to solo rank, I would say ranger, assassin or warrior is the best way to go. A paladin could be decent, provided you aren’t scared of empowerment. Soloing will take a lot longer at higher levels, but at relatively low levels…pre-30 that is, it shouldn’t be bad. I do know that imms do occasionally give a small bonus to ranking solo if you pledge that you will never rank with others(or maybe never ever group, you might have to ask an imm on that but I do know it exists). Mages have a much harder time ranking by themselves, but I bet it is possible. Maybe an utility shifter would have an ok job of it, I don’t know. I hate solo ranking.

On roles, I think it depends on the immortals. Some are going to like story type…some bullet points. I have gotten exp for both, so I think it depends. If you think the 3k exp is better off later on, that’s up to you. I don’t think it matters much in the long run. I just like free exp to tell me that someone liked my role :>
I don’t think in the beginning you get a skill up every level…I think it might have to do with number of skills practiced, but I could be wrong. The number you received (ie if you get 1% in a skill or 4%) is based on wisdom. If you have 25 wisdom you can get a higher skill up than if you had a 18 wisdom. But for the most part, since its random, its not a big deal. Just be happy if you get it in a skill that’s very useful…like sing. Its an added bonus to leveling.

Cabals shouldn’t have a giant “no newbs allowed” sign on them. For the most part(barring conflicting personalities and so forth), if you showed some effort and know what is written in the helpfiles you should at least get someone willing to talk to you about it(ie to explain any other requirements, all of which you should be able to met as a newbie). Some are harder to get into than others. Scions would be an example. But if you want to join the Fort, it shouldn’t be too hard.

If you want to play a paladin, go for it. Empowerment can be irritating if you don’t know what you are doing, but unless you say screw you Amaranthe(or something to that effect) I doubt you will get smited. There have been many newbs who get empowered. It just takes more willingness to write a role and having a stronger role playing presence. If you are looking for shrines you can ask in character. For example if you are looking for Baerinika, you may ask someone who is tattooed by her for assistance. They aren’t likely to walk you over there, but they might point you in the right direction. Religion info is only as forbidden as the characters make it out to be.

You have to look at the mob to get the observation experience for it. In your example, the warrior who looked at more stuff will maybe get an extra edge or two, which would be a benefit. Its not huge enough, though, to make you automatically lose to him. Edges, generally speaking, are small perks to help round your character.

I’m in the opinion that it should be very rare for a goodie to kill a neutral, but if you can justify it through other means…ie cabal and religion, then go for it. If you are an outlander elf, you might slaughter Tarus, and I doubt the imms will care too much. Just make sure you can justify it for reasons beyond shiny gear.

As for your example of your sphere…I don’t think you need to worry about getting smited for not practicing a specific spell or skill. You can argue your character is only interested in forbidden knowledge…or knowledge that will help further your cause, etc. The spheres are just guidelines. As long as you don’t do something contradictory to your sphere, its unlikely anyone is going to notice(at least as far as I can tell).