rodolphe yes you will get the vibration etc and if you have notification forwarding enabled for the profile you will get alerts for the notifications from Whatsapp in the profile you're using. (Just the app name not the content.)
I get such calls from apps like Signal still ring when in a secondary user (you have to return to the user installed to interact/answer etc) unlike telephony. Be aware, AOSP has a hard coded limit of a maximum simultaneous active users of 3. The ONLY user unaffected that stays running constantly is OWNER. If you open 3 secondary users 1 of the previous will be shutdown automatically by the system. If this is your user with Whatsapp for example that would result in you no longer being able to receive calls/messages.