Do the aforementioned situations constitute a valid seclusion (khalwa shar'iyya) necessitating the waiting period (iddah), despite the absence of intercourse, and does the ruling of consummation (al-dukhool) apply to them? And if the husband wishes to take his wife back, does that require a new contract?

Divorce of a woman with whom intercourse has not occurred is an irrevocable divorce (طلاق بائن) for which there is no 'iddah (definition) (waiting period). The husband does not have the right to take her back except with a new contract. The seclusion (khalwah) that is considered equivalent to consummation according to the Hanbalis is that in which sexual intercourse can ordinarily take place. As for enjoying conversations and looking via the internet, or kissing and touching without seclusion, these do not have the ruling of consummation. Based on this, you do not have an 'iddah, and your husband cannot take you back except with a new contract and a new mahr (dowry).