1. Can you get ob/exp as a ghost?

2. If I go to an area that is listed as ALL as a level 1, do I get the same exp/ob as I would if I was 51?

3. Do you get any exp/ob from ALL areas at level 51?

4. What are the levels where you need to have a certain amount of exp
ie(1-10, 10-20, 20-30, 30-40, 40-50)

5. Is it the same for pk? certain amount of PK's to open up edges at x-amount of lvls.

6. If I go to an area that is for lvl 35 as a lvl 36, do I get any ob/exp?

>1. Can you get ob/exp as a ghost?
>
No. In general, the less danger the less explore exp.
>2. If I go to an area that is listed as ALL as a level 1, do I
>get the same exp/ob as I would if I was 51?
>
No. It may not apply to all areas but a rule of thumb would be that it's best for observation/explore to visit an area at the lowest end of the level range listed.
>3. Do you get any exp/ob from ALL areas at level 51?
>
Possibly, though in my experience it would likely be only a small amount.
>4. What are the levels where you need to have a certain amount
>of exp
>ie(1-10, 10-20, 20-30, 30-40, 40-50)
>
Before 30, it's in the help file. (edgepoint specifics)
>5. Is it the same for pk? certain amount of PK's to open up
>edges at x-amount of lvls.
>
PK is scored and accounted differently than Obs/Exp, see help file.
>6. If I go to an area that is for lvl 35 as a lvl 36, do I get
>any ob/exp?
Yes

The thing to remember is that area level ranges (as found under the "areas" command) and EXP/OXP min/max levels do not come from the same source and while they're usually consistent, that's not enforced.

A city may, for example, be listed as 1-51 (or "All") but contain a very high level mob locked away someplace that doesn't count for XP until 40+.

This has been stated before, as have all the answers to OP's questions, though this all sounds pretty accurate as well.