How to measure/predict the difficulty of a conflict?
Questionnaires and measurement scales typically take a lot of revision and validation. Otherwise, it is very common that you measure things you don't intend to measure, are missing relevant options, or omit critical factors entirely.

I'd recommend some piloting and to use existing and validated measures whenever possible.

Some of your items sound incredibly broad to me. Are you going to rate "influence of emotions" on a 7-point scale by asking people "On a scale of 1-7, how emotional do you feel about this situation?" That might be fine, but there's also a ton of nuance to emotion that will be missed.

You also have a lot of factors, so it will take a lot of data to resolve their relative influence (potentially hundreds of cases; thousands if you care about interactions between factors) in order to determine proper weights, and you still need to come up with a ground truth "conflict difficulty" outcome measure. Otherwise you are just guessing at weights which isn't very useful. 

Make sure you have IRB approval before continuing with human subjects research (I've been surprised how unaware some tech people are about regulatory requirements, especially at Academia.SE).

Given this is a bachelors' thesis, it may be sufficient to start some of these processes rather than complete them. It might be simpler to just do an experiment, test two versions of your software, and compare some satisfaction outcomes. You won't know which conflicts were more difficult, but you won't necessarily have to: you can rely on random assignment to assume that the comparison groups are equal.