I have a 2-screen EFIS (G3X) backed up by a TruTrak Gemini miniature PFD. My autopilot (TruTrak as well) is also stand alone and can operate independently in the event of a total EFIS failure. FWIW I have dual Nav/Com's and typically 5 GPS's (1 IFR (GTN 650) and 4 VFR--2 in the EFIS, my tablet, and my iPhone). Finally I have 3 sources for charts/plates: my EFIS, my tablet, and my phone.