It is not logical to make a walk on commitment as a junior or early senior year simply because of all the opportunities which will open up winter and spring of a senior year.
Should the walk on spot be with the 'perfect school', and you would never ever ever need athletic scholarship money, then you must absolutely explore the other non athletic scholarship avenues - academic, merit and need based.
There tends to be very little difference in the treatment of scholarship versus non scholarship athletes. Each receives equipment, training room and fitness support, academic benefits, etc. The biggest difference would come with travel; coaches tend to select a scholarship player to travel versus a walk. This is simply because the program has a financial investment in the scholarship player.
But, it sounds like this is not your daughter's 'perfect school' - so......be patient and continue to reach out to college programs. Today's college volleyball recruiting environment is so fluid; opportunities come open all the time and the family which stays current in their efforts put themselves in the best position!