I dare say Monreal will be higher in the pecking order than Jenkinson, and maybe even Holding (Holding is 20, and unlike Chambers, he has not played at this level before, ever).
Tbh I don't really give a flying f*ck about the "pre-season tour" (real name should be "sponsorship commitments"). They may as well try Iwobi out at CB for all I care.
Liverpool on opening day is the key date I'm focussed on.
I would normally be happy with Chambers, or Gabriel starting, but not both of them, without Kosc or Mert on the pitch. Chambers is too young, and Gabriel too hot-headed, for them to maturely manage our defence. If that does occur then there will be a lot on Cech's shoulders to steer them around. Perhaps Monreal in there, with Gibbs at LB, could be a bit safer...
I am not sure if we are still in the market for a CB, but if we are, then Mertesacker's injury should have us rushing that signing now.