I probably wouldn't do either trade. Dalembert and Telfair do not turn this team into a contender by my estimation.
Dalembert is an expiring and plays great defense, he might give us an inside presence. I'm not sure it is worth giving up 2 second round picks, especially since we have so few 1st rounders). I know we can buy more 2nd rders, but, for a 3 month rental, I don't see the value cause I don't see this.
I think the Telfair trade significantly undervalues both Turiaf and Randolph. Bringing in Dalembert might help the dearth at the backup C position, and then you remove the additional player so that there is no benefit? Turiaf has a player option for $4.3M this coming year. All odds are that he opts out in favor of more money. I would guess he ends up in Orlando next year. I think they would pay him. If he doesn't opt out, I think his contract is more valuable than it is costly, that is, I think it is very tradeable if needed. As for Randolph, we could arguably get a first round pick plus extra. If the reports are to believed, we can get Minnesota to take Curry and Randolph, deliver a 1st Rd pick and Corey Brewer? If we just took back Corey Brewer and the 1st rder we are probably in a better position than that trade.
All in all, I don't have a problem with trading pretty much any player on this roster for the right deal. I don't see the cap savings here as a worthwhile reason to give up some of our few assets.