Mechanical vs Electronic manual shifting

[toddshotrods]

If I understand correctly, when you downshift using paddles on an electronically controlled automatic transmission the transmission kind of freewheels, until the rpm's match the selected gear. When this happens, how does the engine "come back online"? I would guess it's a smooth "re-entry" because of the torque converter. Or, am I dead wrong or slightly misguided on the whole electronic downshifting process?

If you have a street/strip or full manual valve body, and select a lower gear mechanically, via a conventional shifter, isn't the transmission forced to comply. I was told that with a full race valve body it's up to your brain to not tell the transmission to downshift into first at 90mph, because it will do whatever its told. If this is true, wouldn't converter slippage come into play in determining how abrupt or smooth the downshifts are? I know line pressure affects this too, just curious how much the converter factors in.