That might be a timing issue, that’s why the recommendation is to use +Feed in preference to +Input. It certainly should work if, in Input1, you go +Input2 +Input3, or the preferred way: in Input1, go +Feed2 +Feed3.
What you have is, for the emonPi
P1 → emonpi:import → emonpi:import_kWh
P2 → emonpi:solar +input(P4 Garage Solar) +input(emonpi:power1) → emonpi:use → emonpi:use_kWh
and for the emonTx
P4 →emonTx3CM15:P4 → emonTx3CM15:P4_kWh
My first suggestion would be to log the powers that you’re going to use to Feeds, and then use +Feed. That should get rid of timing problems.
Using the numbers, you have for use: 43 + 25 + 2098 = 2166, and it’s logged 2201.87. The discrepancy is exactly the value for emonTx3CM15:P4_kWh so it looks as if you’ve included a kWh value by mistake, but I can’t see where unless you’ve added P4 Garage Solar and it’s actually P4 energy.
According to the screenshot, you haven’t actually added P4 Garage Solar. That makes me doubly suspicious - there’s a mix-up somewhere.
It doesn’t do that, as far as I recall. I think the Solar App simply isn’t capable of using/refuses to see a virtual feed.
This might help: Understanding Virtual Feeds and https://openenergymonitor.org/emon/node/10977
Much better 
I don’t know why a .png should be fuzzy, but it was.