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There's no reason why couldn't run road shifters and MTB RD&FD if you wanted to go 2x. The MTB front derailleurs only word with small chainrings though, so you'd be limited on gearing. I imagine that with all things Shimano the figures they give are conservative and you could probably get away with slightly larger rings than they suggest for MTB FDs. I doubt it would work happily with standard or compact road chainrings though.
You can mullet Shimano (road shifters and MTB rear mech) but only 1X