You do need feedback from the board being programmed. The setup in the 2nd diagram tricks AVRDUDE into thinking it is only talking to one Arduino, when in fact it is talking to many (note that the TX of Arduino-1 is connected). This relies on all Arduinos being identical.
I have just tried this and it works, except that I needed to buffer the DTR and TX signals from the serial interface.
The 1st diagram is safer, but likely still needs extra buffering.
[on further thinking...]
I was using Unos for my test, which have the TX & RX pins permanently connected to the serial interface by 1k resistors. When I tried connecting pin-0 on the 1st to pin-0 on the second, the resistors made a divider chain and halved the signal. This is why I needed a buffer. If I had used Pro-Minis (or any other board without an integrated serial interface) I wouldn't have needed to buffer the serial, although the reset signal would still need it.
The 1st diagram might be ok as drawn, as long as you're using Arduinos without onboard serial interfaces.