For an IFR airplane, you'll need (in addition to VFR equipment):
- Generator or alternator
- Radio (COM/NAV) appropriate to the flight
- Attitude indicator
- Ball (inclinometer)
- Clock
- Altimeter (pressure sensitive)
- Rate of turn indicator
- Directional gyro
I have a Dynon D10A as PFD. Analog airspeed, altimeter, vsi and turn coordinator. A Garmin 200B COM only radio (no nav).
With that kind of equipment, I assume you have an alternator. The GTR200B satisfies the COM portion of needing a radio and the GTX345 the transponder portion. A second COM would be nice, but that radio has monitor mode so that gets you partway there. We'll get to the NAV portion down below. My Dynon history is a bit rusty, but I seem to recall that the STC says it can be primary for AI, clock and altimeter. I also assume that your TC has a ball as well. So the only question is whether you have a DG or if the D10A STC says it can be one (again, rusty on my Dynon history).
A panel mounted Aera 760, but I'm told it can't legally be used for approaches.
Very true. NAV equipment needs permission to be used as primary for IFR. The Aera isn't so blessed. Its manual explicitly says no.
I'm in the northern virginia area and the local airports have ILS, LOC and RNAV approaches. I see VOR approaches at couple further away airports.
The ACS spells out which approaches you'll need. You'll need one precision approach, which means an ILS and this is accomplished by a NAV radio with a glidescope. However, many LPV approaches (a subset of RNAV approaches) can be substituted even though it's technically not considered a precision approach. This is accomplished by an approach certified GPS with WAAS (sometimes called SBAS) capability.
You'll also need to execute a nonprecision approach, which in your list means LOC, VOR or LNAV (another subset of RNAV approaches). For VOR or LOC, you can use the same NAV radio as you used for the ILS. For LNAV, you use a GPS but it does not have to have WAAS.
So in sum, you'll need to add at minimum one NAV radio. However, 2 would be nice because you'll likely have to identify waypoints using intersections. Like your GTR200B, some have a monitor mode so you might be able to use that to identify intersections. But if you want to fly IFR in the real world rather than stop at getting the rating then you'll want a GPS, preferably with WAAS.
EDIT: Forgot to mention that a certified GPS (Aera does not count) may be used as a substitute for identifying intersections.