A has even told us that in her eyes we have already had sex. In some ways she seems to struggle more with what she calls "coupley" stuff, when we cuddle or do other non-sexual things. Perhaps the worst emotional hurdle is over...
Well, it's good she's reporting her emotional weather up front. Could give her props for that.
If your goal is to develop your relationship with H while preserving your friendship with A.... be a friend then. Friends do ask each other how they are doing from time to time.
Could ask her how she's holding up.
Could ask what she needs at this time in terms of support from you as she deal with accepting "the new normal." Is she feeling left out? Not considered? Dealing with envy and wishing she had some of the NRE action herself? Something else? Or basically ok and just needing time to pass?
She may or may not be willing/able to articulate everything but your could inquire about her well being as her friend.
If you are willing to do more than inquire, you could let her know what those things might be.