ANSWER:

No problem in fasting Friday alone for arafat or ashura.

It’s not permissible to fast a day after arafat because its the eid day and its prohibited to fast on eid days and the days of tashreeq (11, 12, 13 of dhul-hajja)

Shiekh, since the day of Arafat this year is falling on Friday, can we fast just the Friday, or do we have to keep a fast before or after Friday as it not recommended to fast on Fridays alone? Please clarify.