That team is definitely a whole lot of mediocre players. If Mayo could rise a level or two, I would review it as a fringe top 4 team in the East.
That team would be very challenged to get by Chicago or Miami. Perhaps they would snatch a game or two. The Pacers and Sixers would probably give that team a whole lot of trouble too, although I think they could be competing for 3rd, 4th and 5th seed. The Knicks and Hawks could be there as well.
Also, I do not buy the trades I am afraid. I think Toronto likes Ed Davis, so giving up JJJ and Bradley for him would be contingent to both players improving significantly from their current performance (albeit JJJ is very much a question mark). And, given that would happen, I'd rather keep them.
Also, why S&T Allen and JO for another expiring contract, when they could just outright sign Kaman? If that would be incentive to obtain Jack, I highly doubt that would fit the Hornets MO. Why stack 'win now' veterans on a team going nowhere? And Pietrus would probably not be around for the vet minimum, I think he could get MLE money, or otherwise sign a more probable contender.
Right now, if the Celtics want to be in contention for the 18th banner in the coming seasons, it to me seems like Howard or bust.