As you have already noted, Microsoft BizTalk 2013 R2 (Host Integration Server 2013 MQSC) does not support working with IBM MQ Client 8.0. It is not even worth trying because BizTalk is using C++ 2008/2010 and IBM MQ Client 8.0 is using C++ 2012. The Process starting application must always be in the highest or equal Runtime that the client/child assemblies.

The only workaround is to use the IBM MQ Client 7.5 to connect to IBM MQ Server 8.0 (which is supported by IBM) :