Hi Jingle,
Welcome to the OCF, sorry that you had to be here but this place is wealth of information and will help you and your husband get through this disease.
Now coming to your questions:
1. The first surgery that your husband had is called Partial glossectomy where they would have removed part of the cancerous tongue. If Neck nodes are affected, the docs would also perform Selective Neck Dissection.
This is usually followed by reconstruction of the tongue. In my father's case (left lateral tongue cancer), they folded the remaining right tongue and attached it back to left. The tongue was shortned but functions were retained. In your husband's case since that was not possible, so to retain functionality, they used the Neck muscle which unfortunately failed. To stop the tongue bleeding they had to cauterize his tongue.
The second surgery (or third) was the second reconstruction using tissue from his forearm (Forearm Free Flap reconstruction).
2. Once feeding tube is removed, you can gradually start with semi-solids. I have not seen any complication in case of my father. Your husband would need to gain some weight to be able to progress with next phase (Concurrent Chemo-radiotherapy) of treatment.
3. I am not aware of any hairy tongue but it may be possible and curable.
Take good care of your husband. As a caregiver, everyday would be a new challenge for you.
All the best.