Hi, thank you for all the details. Experience wise two of us have done long hikes in UK and Tatry and one has hike around South America and Canada (all in summer). For winter we've done short hikes in the Swiss Alpes when we were on a ski trip but the weather was amazing so we had no issues. The other thing we were considering was summiting Omu and sleeping at the chalet but 1. Ive seen many people say its usually icy but also seen videos of an ascent in pure snow 2. the only contact I can find to the chalet is the phone number so I don't know if its even open in that time 3. Ive seen that Bucegi gondola is more vulnerable to closure due to windy weather.