Electronic – What are the resistors bridging connections between devices generally implemented for

It's not a problem but if you are worried that there maybe a conflict of outputs then connect them with a 1k ohm resistor. This will limit the current accordingly.

If however, the input needs really fast edges then when you are sure it is working, bridge the 1k ohm with a short or 100 ohms maybe.

The added bonus of having the resistor is that if you have the design commited to PCB then it gives you an easy re-wire option.

It's the same problem with unused inputs - tie them to ground or Vcc and you risk heavy current draw from the device without any easy way to work out what is going on - tie via a 1k if unused or maybe 10k.

Overload limiting is done on some chips but only by virtue that the transistors cannot inherently supply "amps" but this can work against you because if you have several o/p pins shorted to ground (or each other) and each one is limiting gracefully, you may still exceed the max rating of current into the power pins of the device.

For the MSP430 series 2 page 21 of this document says: -

This tells me that if the combined output currents of several pins hits a certain limit then the output capabilities of any other pins (even those that may be lightly loaded) may be impaired by the same amount or possibly worse.

The CD4050 is a digital logic buffer that can be used to shift signal levels from high to low voltage. It is not a voltage regulator - however you don't need one anyway because the EK-LM4F120XL already has an on-board 3.3V regulator. But perhaps what you are really worried about is the signal levels between your 3.3V MCU and 5V peripherals.

The LM4F120 has 5V tolerant I/O, so you needn't worry about blowing up its inputs. However its outputs can only go up 3.3V, which may not be high enough for devices that expect to see 5V. A standard CMOS logic gate powered by 5V could require a logic high level of least 3.5V for reliable operation (at 3.3V it might still work, but with greater propagation delay and lower noise immunity). Unfortunately that means that the CD4050 is not suitable for level shifting from 3.3V to 5V.

Most servos work fine with a 3.3V input signal, however the LCD display and ranger (and keypad?) might have problems. Check their data sheets to find out what logic levels they require. To level shift outputs from 3.3V to 5V You can use a buffer with TTL compatible inputs, eg. 74HCT4050 (note the 'T' which indicates TTL). If you are using a bidirectional bus such I²C then you may need special level translators that are designed to work in both directions at once.