What is the best way from Beijing Capital Airport to Novotel Beijing Peace Hotel?

Hi, since you have 7 people, including wheelchair mother and young children, you'd better catch two taxis from the airport to the hotel. To visit the Badaling Great Wall(https://www.travelchinaguide.com/china_great_wall/scene/beijing/badaling.htm) , you can take taxi to Deshengmen Gate and then take bus 919 there.
Bus 925 run directly from Deshengmen to Beijing Ming Tombs(https://www.travelchinaguide.com/attraction/beijing/ming_tomb.htm) every 30 minutes in peak hours from 07:10-19:10.