Hi,
1. Full load: we can do full load any time if previous load was failed. But delta as i said repeat delta only we can do when we set last delta as red mark.
2. if your dso delta req was failed to load, then further loads will also fail or no loads. what ever loads you need to correct DSO level and load further.
3. this can be possible at psa only. From dso or cube to further, we need to make correction source targets other wise load won't happen as stated by martin.
if you have sand box try to develop flow like Data source-->DSO--> info cube. test all cases, you will get clear idea.
in production when we receive errors, first need to rectify then only move loads further. depend on the situation we need to think about repeat delta for delta loads.
full load: some time full loads also can't load continue on next day due to source system error, in this place first we need to make correction then only load will continue. for DSO/cube , if we have full/delta red request, loads will won't be continue. need correction then only it will move data further.
Hope it clear.
Thanks