Gleeson will battle samu for no.20.
If I'm Jones and I have 6 back row I'm picking:
Holloway
LSL (Lukhan Salakaia-Loto)
Valetini
Samu/Gleeson
Hooper
Mcreight/Gleeson
Hooper isn't at his best, but I think he has been coasting, same for Samu. They've proven they can make an impact at this level and I still think that's true. And Hooper can still go 80 mins whenever needed.
Samu can substitute at 8 or 7. Mcreight/Hooper are a bit redundant. I don't see Gleeson as anything other than an impact sub. Holloway/LSL (Lukhan Salakaia-Loto) are needed for their size and lineout ability. I prefer LSL (Lukhan Salakaia-Loto) to Hanigan.
So to me it is whether they want a 1 for 1 replacement for Hooper (if not - take Samu+Gleeson over McReight).
Personally I'd roll out:
Holloway-Valetini-Hooper
Sub in whomever looks the best of Samu/Gleeson/LSL (Lukhan Salakaia-Loto) and/or sub in LSL (Lukhan Salakaia-Loto) at lock and bring in Gleeson/Samu.
Based on England all we know about Jones is that he likes size/impact, doesn't care that much about club rugby form, and likes to kick a lot.