Struggling to find confirmation online but it would appear that replays will be going ahead if needed. Seems to be that they may be scrapped in the 3rd and 4th round on a case by case basis for teams in Europe or who have had a number of games postponed already.
"Supporting a football club is about much more than watching football on a Saturday afternoon. It is about the emotional attachment that people have with a club that sticks with them for life"