First reuse of a booster in a couple months is... ambitious. NG1 performed admirably on delivering a payload to orbit, so I'm not terribly concerned about whether the probes will get where they need to go. But landing a booster for the first time, refurbishing it in a short period and launching again only a few months later is a hell of a goal when you have only a vague idea of what condition a returning booster is in.
Wasn't the need to do a suicide burn part of the difficulty in landing a Falcon 9? Is a nearly empty Glenn first stage heavy enough and can the BE-4 throttle low enough to hover if needed, even for a second?