I knew you will ask that and you know I'll tell you that including a module is perfectly fine is this module can do the job.
But, to answer your question, I could not find a way without orpheu. UTIL_LogPrintf is using ALERT which is pfnAlertMessage. I tried using EngFunc_AllertMessage and even calling that function with orpheu instead of fakemeta, but it seems like metamod ignores this calls.
I did not check more than that, but at a first glance it looks like it's not possible without manually calling C_AlertMessage.