Whole house filter will depend on the size of your house. A typical 1 bed/bath house can go with a simple big blue filter like BB-10CAB that filters out chlorine as well as organic chemicals. A larger house may need a backwashing filter like CCMG-0948. Decide the backwashing filter size after getting to know your maximum service flow needs and available backwash flow rates from plumbing lines.
Undersink ro systems are easier to install and yes, they would reduce all heavy metals, chlorine, pesticides, and pharmaceuticals. VGRO-75 is a water saving choice. You won't need more than 75 gallons of drinking water a day.