Hi, my knowledge about electronics is pretty limited. So, sorry for any misconceptions about the topic 
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Some modules have duplicate inputs and/or outputs, like the VCF which has two input pins for the input signal as well as for the cutoff cv and has even four output pins for the resulting signal.
My question now is, are there any things to watch out for with these duplicate inputs and outputs?
If I interpret the circuit diagram correctly, the inputs are added together. But what happens if the two signals combined exceed 5V? Are they clipped at 5V (or how much volts the boundary is in this case ) or are the scaled so that the max input combined does not exceed 5V?
And for the outputs, do they behave like mulitple modules in eurorack. Considering that mulitple modules are also not cheap, I kind of can’t imagine that every Microrack module has one or more multiple-curcuits included, on the other hand I have no idea what I’m talking about so I could be completely wrong . If I understand correctly there is also a difference between buffered and unbuffered mulitples, but that adds just to the confusion for me 
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I’m totaly in love with the duplicate inputs and outputs because it opens up so many use cases without any extra mixers and mulitples, but I want to understand their behaviour correctly to not run into some unexpected behaivor 
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Thanks in advance for any help ,
Jesaja
Ps.: Another question that I don’t want to open another thread for is, what are the differences between the TS cables used in eurorack with a ground wire and the cables that are used by Microrack and Serge for example. I found a few answers online but I would be very happy if someone could explain it to me or link me to some helpful resources 
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The outputs are probably just connected in parallel to the one output of the actual circuit, so they behave like a passive multiple.
I really should not speculate about the inputs; there are several ways to handle them and they all have their pros and cons.
About the cables:
TS cables are shielded, i.e. they have an inner conductor carrying the signal, surrounded by insulation, then a mess of thin grounded wires acting as a shield and then an outer insulation. This helps against two sources of noise (i.e. unwanted signals from outside the synth):
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capacitive: if you grab a cable, your hand, together with the insulation and whatever wire is immediately under the insulation, forms a capacitor that can transfer AC signals into the wire. The human body is a great antenna for al kinds of noise, mostly hum from the power grid, but also the nearest AM radio station (if any). With a shielded cable, that noise goes into the shield and is therefore grounded.
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inductive: any signal wire, together with the nearest ground return path, forms a loop antenna that collects AC magnetic fields. The bigger the area of the loop, the stronger the (unwanted) signal (again mostly grid hum). With a shielded cable, that area ist practically zero, because the return path is right there next to the signal wire.
The capacitive effect does not matter much: it stops when you let go of the cable. Induction also is harmless, while the wires are short, i.e. connecting modules in the same rack. For anything above 50cm or perhaps 1m I’d recommend shielded wires.
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I should say you knowledge of electronics is enough to ask really good and deep questions!
Yes, you are right, most of the modules has two inputs in parallel and signals are added together. It depends on specific module what happens if you put two 5V CV on both inputs.
For example, VCF starts clipping and produce noisy sounds (also if you open cutoff knob and put one 5V CV, you get same result). But VCF has depth amount knob, so you can reduce CV amount.
Another example, VCO: if you put two 5 V CV on pitch input it just starts oscillating on very high frequency, out of audible range.
Sometimes it might be a clever trick to amplify CV: just put two copies of signal on the same input.
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