Don’t count on Christie appointing a Republican replacement. When Democrat Senator Frank Lautenberg died in office in 2013, Christie could have appointed a Republican replacement, but instead he called a special election which resulted in the election of Cory Booker. There could have been one more GOP Senator for at least 18 months, but Christie was running for re-election and he thought it would hurt re-election chances slightly to appoint a GOP Senator. He put his own political prospects ahead of the country. One of the big reasons I lost all respect for him.
I seem to remember something like that, but Republican Jeffrey Chiesa was appointed to replace Lautenberg for about 5 months until Booker was elected in the special election in October 2013. How did that relate to what your posted there?
Actually Christie had an August! primary & October! special election to avoid Nov 2013 turnout for Booker hurting his reelection numbers.