Can the other siblings remove items from the house without informing all the siblings

To a certain extent, it depends on what items you're talking about and what estate planning documents your father had in place.  If items were in a Trust for example, the terms of the Trust would govern what happens with those items.  Generally speaking however, household goods are part of a person's probate estate and nobody has the legal right to remove those items.  They must be inventoried and distributed in accordance with the order of the probate court.