1. Can one be on the computer or phone while the candles are lit? (Reading, chatting, playing games)
2. No fasting on Hannuukah. Does drinking water count as not fasting? (health aside) How much is needed for it not to be fasting?
During the brachos and lighting, we shouod be present and not be involved in other things. Although the person lighting is being motzei others, if possible they should be there, and listen to the brachos, and answer amen. After the candles are lit it is commendable to sit by the candles, owever it is not an obligation.
Regarding fasting on Chanukah, if one drinks water or eats any foiod, it is considered as not fasting.