No, the bonus is not going to happen.
If Tellez clears waivers and then signed with a team as a free agent he would make a pro-rated league minimum salary and the bonus clause dies since it would be a brand new contract.
A team would have to claim him off waivers to take on the contract from the Pirates and if the Brewers (or any other team) did that the last 5 games alone would cost approx. $100K in salary per his existing contract. Then they'd be paying him the extra $200K just for fun, assuming they give him at least 4 at bats, which they definitely wouldn't want to do.
If they were feeling generous they could save $100K and just cut him a check for the $200K as a gift without signing him to their team and it would amount to the same thing.
Either way, the most likely scenario is he goes home a free agent for the remainder of the season and collects the rest of his pay (what remains of the original $3.2M) from the Pirates, minus the bonus.
ETA: I'm not even sure there's enough time left in the season for any of this to happen, I think the waiver period on DFAs is 10 days? He would not be eligible for the postseason for any claiming team.