Yes, Republicans will return to unity as they return to their core values. After Reagan, the GOP has been in a state of gradual decline with neoconservative and globalist overtones that doesn't jive with the voter base. The rise of Trump is the grassroots protesting slick establishment lackeys like Mitt Romney who have neither understanding nor care for regular people. There will be a lot of former GOP power players tossed out in the coming years, but the remaining party will grow stronger as the lackeys are replaced by true conservatives.
Republicans have one person that can most likely unify their party: Hillary Clinton. Clinton has very high negative numbers with the electorate, especially with Republicans. Most GOP voters will be more motivated to vote against Clinton then they will be to vote for Donald Trump. Therefore, GOP unity is still very possible.
This presidential election has produced some very interesting nominees, especially for the Republican part. Donald Trump has said some very outlandish things and has some very skewed view points on a variety of topics. Many of his beliefs and opinions are not what many republicans politicians agree with. Despite being nominated as the presidential nominee, many republican politificans just done feel he is the right choice for president.
Trump thinks he is being very clever by choosing someone that will stand up against the establishment. This approach worked in the U.K. Brexit vote with the larger percentage of people choosing to vote "Out" as a protest against the establishment. This split the Conservative party causing several key people to lose their jobs. The same thing will happen with the Republican Party.