I'll forward your questions to LMB, correcting the spelling of her characters and removing your question about Simon Illyan's first name.
But I can anticipate some of her answers: none of your candidates seem likely.
A Count is not a figurehead as are kings in the UK or Scandinavia. They are expected, at least, to take a real part in the affairs of their district. Poor Simon may have somewhat recovered after the destruction of his memory-chip but is definitely not up to such a demanding task. This is even more true for the Viceroyalty.
Koudelka is in slightly better shape, but still too old and crippled. It would be cruel to appoint him, he'd kill himself doing his best trying to be up to the job. And Drou would veto it, no doubt. What, be wormholes away from her daughters ?
Galeni is interested in integrating Komarr to the Imperium. All his military carrer is oriented in that direction. What he would aim for is some high position in the staff of Komarr's Viceroy (sorry, the Komarr Imperial Councilor, as he is styled), or maybe become Imperial Councilor himself ! Ruling some District in Sergyar would take him far away from there.
Consul Vorlynkin ? Clearly, he did a good job, therefore he deserves a new one. First, upgrade Barrayar's representation to Kibou Daini to Embassy level, with him as Ambassador, sure. Then maybe a move to a more important place, Escobar or Eta Ceta for instance. If he does a super job there, maybe, but if no special new crises come up, for him to show exceptional qualities, he certainly has not yet done enough to be promoted Count on Sergyar.
And Alys and Simon surely have reached the age when you are eager to have grand-children (or step-grandchildren), not children of your own!
Human is as human does....Animals don't weep, Nine
LMB, The Labyrinth