You need your old phone and delete the banking app on it first before trying on the new phone and yes turn off wifi first and use data. Did this at two different banks easy if you have your old phone.
I agree only took about less then 10 minutes at K Bank but you need your old phone and delete the banking app on the old phone first. Same for Krung Thai. Wouldn't work if you don't delete app on old phone first. Sim card in wife's name no problem there either.
I agree bring it along we always took ours to Bangkok for the twins. Also we had a harness for both kids to keep them from running around or into traffic.