I agree that the part of the course about verbal aspect overcomplicates things. I am fluent in another Slavic language (not Ukrainian) and I notice how the course really struggles to fit phrases into English without being too worried about being similar to natural speaking.
Mm, I think there doesn't have to be any struggle :) Anything can be natural given a context.
I will do it -> Я зроблю, робитиму, буду робити
I will have done it -> the same + Я закінчу робити
Я зроблю -> I will do it, will have done it, will finish it, finish doing it, am going to do it (also fine)
Я робитиму -> I will do it, I will be doing it, I will have been doing it, am going to do
I think those are enough to cover any possible situation :D :D
How is this most commonly used? I will finish doing it tomorrow, I will do it tomorrow, or I will have done it tomorrow?
I think the course overcomplicates this a little. I'm speaking as someone fluent in Russian and English (not Ukrainian), but assume that in this case the Ukrainian meaning is the same as the Russian. In Russian, the corresponding sentence "Я сделаю это завтра" would simply mean "I will do it tomorrow". Yes, the implication is that "I will start and finish doing it tomorrow", but it's not necessary to think of it this way, as in English "will do it tomorrow" also implies "will start and finish it tomorrow".
"I will start and finish doing it tomorrow", I believe. But "I will finish doing it tomorrow" is also common
If you say; I will finish doing it tomorrow", it may mean the action or job has started already and this action will be done by tomorrow. therefore, we have to clarify what "Я зроблю це завтра." really means. Is it "I will be doing this tomorrow" ( I think "з" adds the meaning of "will" to this action , instead of " Я буду робити це завтра". Literally this sentence is correct for " I will do it tomorrow". In this case, the translation of the system is wrong. Am I right? "Я зроблю це завтра." The correct translation should be: " I will be done it by tomorrow" ... not I will finish doing it tomorrow." ( once again, this means, the action has started and the person promises to finish it by tomorrow. But we don't know whether it has started or not." this is what I think.
'Я зроблю' is in the future tense perfective aspect and so can be translated as 'I will do/I will have done/I will make/I will have made'. The English translations include the both the future simple and the future perfect tenses as that is how the tense aspects in Ukrainian map to English tenses (roughly speaking, although there are different ways to talk about the future using the present tense in English and Ukrainian, so translating and interpreting the meaning can be complicated by the context; sentence-based translation without context leads to multiple possibilities.