I think Eklund should have NHL time as much as possible this year, even if he is not 100% ready and producing. Play him with Hertl and Duclair.
You can't bring them all at the same time, so bring Eklund now to get the experience, after trade deadline and next year bring the next that's shown he is ready. That way we take away the risk of too many rookies being here at the same taking the whole team on their back.
Peterson and Thrun showed enough to have my trust for at least getting their start at the big club. It's just important to trust your young players, give them the long leash when they come up. They've done something right to come up.