No sign of a struggle , the flat tidy along with no sign of forced entry and nothing apparently missing
she didnt arrive home at all IMO.
Somewhere along her journey home JY was joined by someone and whether amicably or by force was taken elsewhere. This leaves her belongings. They were placed back in the flat by someone who had a key or the means to enter.
Thats the part that really intrigues me
no sign of force of entry and no evidence of a struggle. Someone lying in wait who took JY by surprise would have resulted in some kind of a struggle. It seems that there was no sign of that!
If I had been out at some Christmas get together and had a few drinks (assuming thats what J did ), then collect a couple of items from local shops on the way home ,walk home on a bitterly cold night with snow underfoot as J did I would have opened the door, kicked off my boots, thrown my coat on a chair !
Had I have been her, alone with no one to tend to then I would have flopped in front of the TV with a glass of wine. I would have just wanted to get warm, feed/cuddle my cat and relax! perhaps an early night. No way would I have left my belongings in the usual place and I certainly wouldnt have been bothered cooking a pizza at 9.00pm. The fact that there is no evidence that J ever cooked/ate the pizza tells me she was never there.
Someone let themselves into JY flat and tried to make it look like she had been home but somehow just didnt get it right.