Go with your gut. Remember there's only two games left, so you need to consider opponents a lot more so than recent form at this time of year.
First combo: Ignoring the mid eligibility, assuming you want them as a DEF only. Witherden has been one of the Eagles best lately, except against North. Lloyd and Hinge have been fairly consistent around 100 in recent weeks. Short and Duncan don't stand out as the best pick to me. Agree on Witherden, just ahead of Lloyd.
Second combo: Comparing two MF v a D. Depends who this will be replacing on field. You know what you'll get with Dale, Bolton is more up and down, don't think Dusty scores as well with little to play for. I would go for Bolton based on match ups, but Dale is the safer pick.