Yes you do
No, you cannot.
T - twin and/or triple trailers N - tanker endorsement H - hazardous materials endorsement Most states will place an X endorsement on the licence of a driver if they have N and H endorsements - X is a combination of hazmat and tanker.
Yes. If it requires a tanker with an unrestricted CDL, so it does with a permit, as well.
The X endorsement is a combination of two endorsements - Hazmat (H) and tanker (K).
They require a tanker endorsement, and most commodities they haul also require the driver to have a hazmat endorsement.
Yes. No differentiation is made between liquid and dry bulk tankers in this regard.
X is a combination of Hazmat (H) and tanker (N) endorsements.
As for endorsements exclusive to a CDL, you can get hazmat, passenger, and tanker endorsements. You can also get a motorcycle endorsement, which can be placed on any class of licence. The only endorsement you wouldn't be able to get is the endorsement for double and triple trailers.
No. Tanker is just a written test.
HME won't be seen on a CDL - the endorsement for hazmat on a CDL is H, or X if it's in conjunction with a tanker endorsement. HME is often used as a shortened form of "hazmat (or 'hazardous materials') endorsement".
Yes. Tank trucks require a tanker endorsement, and the tanker endorsement can only be put onto a CDL. A permanently mounted tank requires one (the regs don't specify a minimum capacity), as do portable tanks of more than 1000 gallons.