Ah yes the phone needed a SIM for activation (some configurations are carrier or country dependent and the SIM ties you in somewhere).
You can remove it afterwards and be on wifi.
If she did not need 4G capability with didn’t you go for a iPad or iPod touch ?
As for apps - need to be specific. Android is all over the place, it’s not even one thing there are as many versions as there are phone operators which all add their layer and dependencies and bloatware…