UPDATE: 05/05/2023
Upon hearing nothing from Presonus RE ATOM mapping solutions to original below issue since 02/17/2023, we decided to remove the ATOM from the recording process completely.
We replaced the ATOM with...
Simmons SD1250 Electronic Drum Kit With Mesh Pads which integrated seamlessly w/Studio One DAW and our iPad.
Wish we never purchased the ATOM which turned out to be a complete waste of time/money..will probably return to Akai MPD218 Midi Pad Controller for future sessions employing need for additional pad controllers (i.e. Dance, Urban, Techno, Trap, etc.).
02/17/2023 [ORIGINAL POST BELOW]
After painstakingly mapping each desired EZ Drummer 2 drum midi Note Value (below) from the extra purchased packs to pads 1-16 in Studio One 6 Producer's Impact XT Pad Bank "A" (below)
using the Akai MPD218 Midi Pad Controller (below) which recognized the entered Midi Note Value mapping and played the desired drum samples correctly when triggered in real time once routed to EZ Drummer 2 plug-in.
Unfortunately, we replaced the MPD218 with a PreSonus ATOM Production & Performance Midi Pad Controller (above) in a effort to streamline the recording process via the additional controller buttons...this turned out to be a bad decision.
The PreSonus ATOM ignores the aforementioned Note Value mapping made in Impact XT "Pad Bank A" and triggers what it wants in EZ Drummer 2.
Pad 1 = Kick
Pad 2 = Sidestick
Pad 3 = Snare Center
Pad 4 = Snare Center?
Pad 5 = Unknown Snare
Pad 6 = Tom 4
Pad 7 = Hi Hat Closed
Pad 8 = Tom 4
Pad 9 = Pedal Hi Hat Closed
Pad 10 = Tom 3
Pad 11 = Hi-Hat Open
Pad 12 = Tom 2
Pad 13 = Tom 1
Pad 14 = Crash Left
Pad 15 = Crash Choke Left
Pad 16 = Ride Edge
We later discovered in the manual each pad has Note Values...but they can't be tweaked in the DAW?
Pad 1 = C1
Pad 2 = C#1
Pad 3 = D1
Pad 4 = D#1
Pad 5 = E1
Pad 6 = F1
Pad 7 = F#1
Pad 8 = G1
Pad 9 = G#1
Pad 10 = A1
Pad 11 = A#1
Pad 12 = B1
Pad 13 = C1
Pad 14 = C#2
Pad 15 = D2
Pad 16 = D#2
Please advise when it will becomes possible to program/reconfigure Atom pads to send/respond to the Midi Key or Note Value # desired to trigger the EZ Drummer 2 sound(s) in real time the way I was able to via the MPD218 which was used to create Impact XT Pad Bank "B", "C", "D" & "E" by dragging desired files to pads 1-16. It's a hassle to have to roll-off each played EZ Drummer 2 instrument sample to create audio samples to drag onto the desired 1-16 pads and still remain unable to utilize the full functions (Ambient, OH Mics, Reverb, Kit Compression, Humanize, etc.) of why EZ Drummer 2 was purchased in the 1st place...to make recording drums easier, right? 
The Akai MPD218 Midi Pad Controller doesn't have this programming bug...awaiting resolution(s).