On a WAAS-capable GPS approach, what is the significance of “LNAV+V” being displayed?

During IFR operation using an approved GPS system for navigation,

Which indications will a pilot receive where an IM is installed on a front course ILS approach?

What are the primary benefits of satellite based area navigation (RNAV)?

(Refer to figures 96 and 97.) To which aircraft position(s) does HSI presentation “G” correspond?