CRJ-900 Captain reported encountering windshear and wake turbulence in trail of a B767 that resulted in an unstabilized approach and a hard landing at ATL.

Narrative

I was the CA/PM on Aircraft X from ZZZ to ATL. We were filed for the JJEDI Arrival and were anticipating Runway 28. The weather in ATL was VMC conditions but winds were reported as 330 at around 20 with gusts to 35 or more. During the descent phase; we were assigned Runway 27L so; since it was a single FMS CRJ-900; I loaded and briefed the approach myself as the PM. As we approached the end of the arrival; ATC advised us to slow to 210 since we would be following a heavy 767 going to 27L. ATC then directed us to a 320 heading to join final and cleared us for a visual approach to 27L.We continued to slow to keep separation with the heavy aircraft in front of us. However; given the winds and the intercept course; our current track had us joining final inside the final approach fix and above glideslope so I directed the FO to go back to Heading mode and turn right for a better intercept course. As we were joining final; Tower reported that the previous aircraft had reported a windshear caution and a gain of 20 kt. crossing the threshold so I reviewed windshear procedures with the FO. The heavy aircraft in front of us also reported windshear and gain of 25 kt. crossing the threshold. As we continued on the approach; we had a short instance of wake turbulence but continued on the approach. Around 700 ft.; the FO disconnected the autopilot and continued with a stabilized approach. Due to the gusty winds; I directed him to try to keep the airspeed at the top of the bug which; with a Vref of 138; would put it at 148. At around 300 ft.; we experienced a strong wind gust; the windshear caution; and the IAS spiked to a max of 172 kt. from which exceed the flaps 45 limit of 170 and resulted in the warning tone. The FO reduced power to control the airspeed and I reported ref plus 12' [at] the 100-ft. prompt. With a lower than usual power setting; we then experienced a sharp decrease in airspeed as we descended below the level of the terminal. The aircraft started to settle and sink rate increased and I called for power 3 - 4 times as we descended below 50 ft. The FO responded accordingly and increased the flare but the aircraft continued to settle at an elevated rate which resulted in a harder than usual landing. After the initial touchdown; the nose yawed to the right and I took control of the aircraft in order to prevent a bounced landing and second touchdown with the nose out of runway alignment. We taxied clear; continued to the gate and reviewed the sequence of events. The flaps overspeed and hard landing was the result of several factors. The first was the windshear conditions and gusty winds at the airport. The highest wind conditions were reported at 100 ft. above touchdown which resulted in a flap overspeed and the FO reducing power. This occurred just prior to descending below the level of the airport terminal which; given the winds were 330 at 20 with gusts to around 35 kt.; effectively screened the aircraft from the wind thereby creating an underpowered aircraft state immediately after an overpowered aircraft state. In addition; we were sequenced behind a heavy 767 with minimal separation which added to the task saturation element of the event and the fact that the low experience level of the FO combined for a situation that resulted in the hard landing and my assuming control of the aircraft.In retrospect; there were options that may have prevented this situation that were not explored. First; given the winds knowing how the geometry of the airport might impact the landing; I could have requested Runway 28. Given the distance from the airport terminal and the fact that heavy aircraft are assigned Runway 27L; it would have eliminated 2 of the risk factors involved. However; due to the time of day and VMC conditions; I do not believe that Runway 28 was manned and available even if I had asked for it. In addition; we were not aware that we were following a heavy aircraft until we were joining final and were cleared forthe approach and were notified about windshear conditions and previous aircraft experiencing gains of 20+ kt. at 100 ft. until we were on final. While simply taking the controls would have been an option; I didn't feel it was necessary and would have created a hazardous situation in and of itself with a control swap at that point of the approach."