If you are working in an academic institution, and training young scientists is an important aspect of your job and career, then you should give higher priority to the “local people” option. Especially if you are using a training grant, outsourcing may not even be a valid option for you. It is true that this option will likely take longer time and cost considerably more, but isn’t this also true for all other work in your lab? Having students and inexperienced trainees do the work - letting them make (sometimes expensive) mistakes and learn through those mistakes - is just part of the process. It will give you a sense of accomplishment seeing your students and trainees overcome obstacles and finally reach the finish line.
Having your own people complete at least some of the bioinformatics work offers an additional advantage: it will help you gradually build up some bioinformatics capability in your own lab. Let’s face it: bioinformatics will play an increasingly important role for many research projects in many research labs in the years to come. You would want to have some local bioinformatics capability to handle at least some of the basic bioinformatics work, and seek outside help only for the more challenging bioinformatics problems. Think this way: having your own people try out some of the routine bioinformatics work is an investment you are making towards building up your basic bioinformatics capability, which you will benefit from in the longer run.