While you are targeting a specific device or a very limited set of devices, the proposed solution is good enough. But if your goal is a public application that will be installed on different platforms, including the future version of Android N and customized ROMs, including, for example, Samsung, you should be careful with the system dependencies of these libraries.
Although OpenSLES and OpenMAXAL are innocent (they depend only on liblog and libwilhelm), the latter requires more caution.
Looking at Android.mk , libwilhelm depends on liblog libutils libmedia libbinder libstagefright libstagefright_foundation libcutils libgui libdl libeffects and libstagefright_http_support .
Only liblog and libdl are "official" (i.e. part of the NDK). Others are platform dependent, and their exported features may not be compatible for different devices running on the same platform level.
To be safe, I would only submit corrections and continue to use the system version of libwilhelm whenever possible. I hope you can reduce your system dependencies this way.