Due to timing conveniences, I started renovations for my brand new HDB flat during the 7th month hungry ghost period. The ID did a good job and the renovations went smoothly. I have since sold the flat and am awaiting to move into a new private apartment.
Personally, I have no hesitations in buying a new home / starting renovations / moving house anytime during the year, hungry ghost or no hungry ghost. When moving house, I have enough things to coordinate and take care off without having to worry about such stuff
Although I do not have any empirical evidence, I seriously doubt that renovations started during the Hungry Ghost month will experience more difficulties/problems than renovations started at other times of the year.
But of course if you have family members who are the superstitious sort, then it's best to avoid creating trouble for yourself. You will never win the "I told you so" argument if things do go wrong, however irrational it might be.
Cheers.