The Battle of Cambrai saw a major use of the 'Fighter Bomber' concept, Orders for I Brigade and Ninth Wing. It mentions at '4 (c)' that two scouts would be 'bombed up' ready to attack when called for throughout the day as would 12 Corps aircraft '4 (d)'. The airfields would be connected to the front telephone network as well as the RFC wireless, Corps aircraft on Counter Attack Patrols could wireless in reports of enemy troops.
Yes they did, there are plenty of examples of this, across the front, in Belgium as well as France and during the 100 Days' Offensive in 1918 the practise became commonplace. This is a mural on a building in Flanders very close to Polygon Wood, where the Australians and Kiwis had a bit of a rough time against the Germans in 1917, around the same time as the disastrous attack at Passendale.
Also, Wadi Haifa and the Battle of Meggido ranks as a supreme example of the use of air interdiction in 1918, but it remains little known about. Here's a passage from the wiki page:
"On 21 September, the Seventh Army was spotted by aircraft in a defile west of the river. The RAF proceeded to bomb the retreating army and destroyed the entire column. Waves of bombing and strafing aircraft passed over the column every three minutes and although the operation had been intended to last for five hours, the Seventh Army was routed in 60 minutes. The wreckage of the destroyed column stretched over 6 miles (9.7 km). British cavalry later found 87 guns, 55 motor-lorries, 4 motor-cars, 75 carts, 837 four-wheeled wagons, and scores of water-carts and field-kitchens destroyed or abandoned on the road. Many Ottoman soldiers were killed and the survivors were scattered and leaderless. Lawrence later wrote that "the RAF lost four killed. The Turks lost a corps."
From here: Battle of Megiddo (1918) - Wikipedia