Naming Compounds

Is the following compound 6-ethyl-3,4,6-trimethyl-3-octene? If not, what is it?

            CH3   CH3
            |        |
CH3CH2CCH2C=CCH3
            |            |
            CH2       CH2
            |            |
            CH3       CH3


What is the name of this compound? (The H by itself on the end is confusing me)

             CH3
             |
     CH3-C=C-H
                 |
                 CH2-CH2-CH3


What is the name of this compound? Is it a cis-trans isomer? The substituentes aren't even on the opposite sides of the double bond though.  Also, not sure what to do about the two lone H's.

        H     CH3
        |      |
CH3-C=C-C-CH3
            |  |
            H CH3



Is this compound 2,6-dimethyl-4-propyl-2-heptene?  If not, what is it?


       CH3                 CH3
       |                      |
CH3-C=CH-CH-CH2-CH-Ch3
                 |
                 CH(CH3)2