if you have already done the first time 90 days notification physically at immigration, then you can file the subsequent 90 days notification online and it must show approved via email which will tell you when is your next 90 days notification due. Any late submission will have penalty. Not checking online but must file online and on time.
yes correct. If you have already done the very first time at the immigration center, then the subsequent 90 days notification can be done via online which do not require the TM30.
if your landlord has lodged it within 24 hours after you reached Bangkok. If submitted late, there will be a penalty to the landlord. If landlord didn’t pay for the penalty, then you will have to pay it. There should be a reference number on top if the landlord has lodged it via the apps.