Hi Sophia, first of all, welcome here!
Second, because you asked - I do answer if someone directs the question, directly.
I am astonished that you started with Fugitive Prince, which is not, in fact, book I! Kudos to you for the midstream plunge, and hopefully you found the other volumes, prior, eventually.
Answer to 1, 2, 5 succession of title on Paravia…there is an appendix on this subject in Stormed Fortress - if you read that, then you know that succession falls into 3 catagories:
Royal lineage, Free Wilds clan, and town rule, and that town rule splits into two catagories: towns which were once Paravian built, and ones that were permitted for settlement under charter law.
For Royal lines, free wild clan, and Paravian fortress: there are shades of responsibility, here. Royal succession is ALWAYS chosen by Fellowship sanction. The crown seat is not always held for life term.
Free wilds clans: chosen by the king, or by clan council - which is a collective of elders and chieftains (plural). Chieftains are electively picked, and head a territory along with elders - Free wilds clans CAN have their succession choice 'upset' by Fellowship Sorcerers in times of threat.
Towns with Paravian origins are ALSO energetic resonance sites - those rulers would be chosen by High Kings, subject, again, to Fellowship authority.
Towns not under Paravian origins are ruled by election - sometimes those elected positions are lifeterm.
Which brings us to Ianfar - he was 'heir designate' which means, chosen by clan council. IF Maenol had progeny, and IF there was a candidate Fellowship power chose to upset the designate heir - then Ianfar's succession could be shifted. The entire clan population in Tysan, at that moment, was under heavy threat, and stayed so, for a long time. Maenol was, therefore, hedging his bets. He foresaw that clan presence in Tysan might be wiped out, or, driven so far into hiding as to be ineffective. Getting Ianfar out, with a clear title to inherit, was a survival move to widen the power base in event everything went wrong.
Sevrand: was the strongest choice for Bransian's heir - didn't matter if it was patrilineal or matrilineal descent. Atheran descent in the clans always went by MERIT, and bloodline, not by family, not by 'oldest to youngest'. Witness: Jeynsa chosen as an infant over two brothers.
Liesse was married as Duchess, she never ruled.
Dawr - didn't carry the title, no; again, she was dowager by marriage.
Question 6) your chieftain would have been elect by a clan council, without regard to descent from a recognized heir…(in case you have not figured it out, the titular posts had to do with Liaison with High Kings/execution of Paravian law. Not secular law - handled by councils and chieftains.
Question 3) In some mythos, it is believed that the soul names the child. I used the Paravian names, originally, so I COULD KEEP THE CHARACTERS straight - it was the brilliant stepchild of my first editor to put the translations in the glossary - and I'd had those names in place, at the time, for two decades.
7) Diarin lived and died in Hanshire.
There you go - anything more?