Low voltage cutoff circuit with USB reset
Assuming the TC54 you draw is the Microchip voltage monitor, that is already a sort of hysteresis intself.

Your schematic is still relatively simple, and your own analysis is pretty much right.

You need to be aware, however that the TC54 has an open-drain output, and doesn't pull to the V+ itself. Only the TC54VC has the extra transistor to drive the output. So unless you are using the VC model, you should make R9 go from V+ to the TC54 output, in stead of going to GND.

With regards to uneven current sharing between T4 and T5 that's a non-issue, because they will only ever need to pull a fraction of a mA, so even if one is taking all the current, that's still MUCH less than it can handle. The risk of heating and uneven sharing is when you are putting transistors parallel to have them sink (or source in case of a PNP) more current than only one single could.

If you put transistors parallel in a circuit where the current will never be higher than what the weakest can handle in the worst case scenario, you don't need to think about uneven heating problems in that regard.

To make it more tangible: If you have 2 transistors that can do 0.5A each, but you want to sink 0.7A, then you can put them parallel, but if they then heat up unequally, or if they are produced with a large margin, one can get the full 0.7A, which is 0.2A more than it can handle.

But in your setup these transistors should both easily sink 10mA, where the current cannot be above 5V divided by 10kOhm = 0.5mA, which is negligible in any scenario.

So, yes this should work, if you have the TC54VC model that has Low output when the input is below the set level. I haven't checked if they also have models that go high when the voltage is too low, but I don't think so.

If you have a TC54 with no VC behind the name, you need to move the R9 resistor as I just pointed out and it should still work perfectly fine.