The annual NP pass is $80 and individual fees into the parks you mention will be [I think] $65, so unless you are visiting other parks, planning on coming back within 12 months, or have family in the USA who could use it with the second name option, it is not worth it.
Helicopter tours from Vegas generally go to the West rim which is not part of the National park. Near to the south entrance of GC is the Grand canyon airport in Tusayan where you can take short flights over the south rim to the north rim and back, but no aircraft can land in the NP area. We used Papillon from GC airport and took a 50min flight and all I can sy is, Awesome !!
Harley D rental is going to be specialist and therefor expensive with no way around it. All you can do is search for options and see what the best deal turns up.
Have a great trip and we will look forward to hearing all about it !
