It is going to be a fun team to root for, but not elite defensively. It takes time for bigs (especially those who played zone in college, like Turner) to pick up defensive concepts, especially pick and roll coverage. So, initially, we would have 1 huge and 2 big defensive liabilities - Thomas, Sullinger, and Turner. (On a related note - Sullinger's d is not bad - I argued this for years, but it is conditional on other team members). Also, assimilating two rookie into starting lineup is almost unprecedented and Celtics definitely would not do it (Smart did not start for a half of the season anyway). Also, getting two lottery mid-rounders is not really feasible, although I do believe you can get #12 or better for Bradley alone.
My idea for improvement would be as follows:
1. Use Rondo trade exception to absurd Noah. Chicago will do it because otherwise they will have to pay tax after they extend Butler. If Noah's knees are no good and he does not play then his contract is an expiring - no damage done long term. If he plays then we need a much needed defensive center for nothing.
2. Look for Wallace trade at the deadline. His contract would lose half of the value and there might be a disgruntled star available. Also, value of Nets pick would be more clear.
3. Try to trade up in a draft using Olynyk and picks - we have too many power forwards as is.
4. Keep Bradley until the trade deadline. He is exactly the kind of player that is included in a deal for an established superstar - young, productive and on a long, team-friendly contract.
Basically, what I am trying to say, incremental improvement is better than gambling on some unproven draft prospects.