Looks like a haunted house with both old and new non-humanoid youkai (does a phone-youkai even exist?). It'd be fun if Marisa drifted in the outside world without her magic, and has to fight them (or, for once, escape from them) to get back in Gensokyo.
Can anyone translate what it says in the child post?
Also, is that a flashlight Marisa's holding? IIRC, Marisa was using a flashlight against Cirno in Great Fairy Wars, so there may be a possible connection here.