GPU miners to dev:
Dero Atlantis:
ASIC resistant?
plainly: YES/NO

Not a dev but, it has been stated numerous times. YES, ASIC resistant.
some link where dev confirms it?
Just read the last dozen pages, it's been asked and confirmed plenty of times.
I probably overlooked, so you have a concrete link? (from dev)
If you don't trust somebody else's word than perhaps you should look for yourself next time. It doesn't take much to realize that it will have to be ASIC resistant as the PoW is changing. Since it is a new PoW, there are no ASICs built for it yet.
I am not going to scour the ANN for you but there are official responses from the team confirming this multiple times. Here is a quote from the April Monthly update.
https://forum.dero.io/t/dero-monthly-update/446"Specific Updates:
Source code: DERO project source code will be availiable in coming weeks.
POW: POW will be defintely changed to make it more egailtarian in DERO-Atlantis. Few algorithms have been short listed for DEROs next POW and are under tests to handle scalabilty, verifiabilty, DoS issues etc. Right now there is no change in POW as we are already in process of migration to new blockchain next month."
Now, that statement is from April so don't get confused. What it means is that they had not changed PoW in April because they were going to release the new blockchain with Atlantis.