The 4-pin EPS is optional on that motherboard, correct. I am surprised the 2 existing 8-pin EPS connectors are not 4+4 already... or at least one of them.
If you have an additional EPS 8-pin that is 4+4 and the others you mention are not, you can use that, correct.
If you have an additional EPS 8-pin that is 4+4 and the others you mention are not, you can use that, correct.