I think you should at least talk to your dad to see how he feels about the issue. My dad and I don't have the closest relationship, but I am pretty sure he would be hurt if he didn't walk me down the aisle. Personally, I would rather walk down the aisle myself, but I don't feel it is worth it to hurt his feelings. So check with him first.
As for your sister, I would have her walk down the aisle and stand up at the front like you would normally do. The groomsmen don't always walk down the aisle so this will not appear odd.
In the end, it is your day so you need to do things the right way for you!