The big US grain agreement with the Soviet Union was signed under President Ford in October 1975, and it covers grain purchases, not emigration. Congress did tie Soviet trade benefits to letting people leave through the 1974 Jackson-Vanik amendment, and Jewish emigration rose in the late 1970s. But there is no documented Carter deal swapping grain for emigrants, and Carter's best-known grain move was the 1980 embargo against the Soviets.
Soviet comedy was tightly controlled by the state, and Arkady Raikin was its biggest star. But there were far more than about two approved comedians. Gennady Khazanov performed through Moscontsert, a Moscow state concert agency, from 1973, and the duo Roman Kartsev and Viktor Ilchenko and the writer Mikhail Zhvanetsky were also well known, state-sanctioned humorists in the 1970s.