No, unless you're hauling something which requires a hazmat endorsement, such as contaminated soil.
26000 lbs = 11793 kg
No.
If the Gross Vehicle Weight Rating - not the actual laden weight at the time - is under 26,000 lbs., then no. You will, however, need a current and valid DOT medical card.
To answer you we need to know what country's traffic regulations you are asking about.
Depends on what the Gross Vehicle Weight Rating of a vehicle is. For something like an F750 which is licensed at 26000 lbs or less, you don't need one. 26,001 lbs. GVWR or more, you'll need a Class B.
26000 lbs of cargo? A tandem straight truck, such as a flatbed or a dump, could haul that amount of weight legally.
average school bus weighs about 7 ton (14000) lbs if gross weight was over 26000 lbs
So long as the Gross Combination Weight Rating of the two vehicles is less than 26,001 lbs., then no.
The average school bus weighs about 7 ton (14000) lbs if gross weight was over 26000 lbs the driver would need a CDL not a bus drivers endorsement and most have air over hydraulic brakes
No.. not unless it's either a passenger bus designed to transport more than 15 persons (including the driver) or a vehicle carrying a quantity of hazmat which requires placards to be displayed... in both instances, you'd need a CDL, whether for intrastate or interstate use. If the vehicle's GVWR exceeds 10,000 lbs., you will, however, need a DOT medical card.
Only if it's either carrying hazardous materials or else is a bus designed to transport more than 15 persons (including the driver).