An irregular trooper using either an impetuous order, or a regular order from its order pool, finds itself isolated in its active turn. At this point it has not spent its irregular order. Does it still have access to the irregular order it generated for itself during the order count phase? my assumption is yes, as the irregular order is attached to the model and not the models' order pool, thus spending that irregular order is not spending an order from the order pool.
Isolated prevents it from spending orders from the pool, Irregular orders aren't added to that pool, so your assumption checks out, IMO.
I see it the same way. so if in the prospect of getting isolated, use a regular order first and then happily use the irregular one while being isolated.
so it means if my Leitenant get isolated during my turn, but still not spend his leitenant order, he can use it on himself?
Yes. When Isolated the Trooper can't receive orders from the Order Pool. A Lieutenant Special Order is not part of the order pool. "The Lieutenant of each army has a special extra Order that is for his use only. This Order is not included in the Order Pool, but kept separate for the Lieutenant to use."
And in the case of a LT with strategos, with the LT order going to the pool as a regular order? How does that interact? It happened in one of my games, I isolated the enemy Avatar, and we didn't know if he could use his LT order or not...
In this case the Lt order is in the pool, so your isolated LT couldn't spend the LTOrder, because strategos he have none LTOrder, it is in the pool.
Yeah, Strategos says you straight up replace the Lt Order with a Regular one at the beginning of the turn. Weird side thought, can an isolated NCO still use the Lt. order?
(Annoyingly I can't get to the wiki to confirm, but...) Doesn't an Isolated Lt put you into Loss-of-Lt anyway? IIRC it's the only way to get a G:Mnemonica army in LoL. In which case, there's no Lt orders at all to worry about.
You could also kill all models that aren't REMs without G:Autotool... but at that point, they are probably in retreat anyway.
This. Your Lt doesn't change until the start of your next turn (G:Manamama and CoC excepted). This is also important if your Lt enters a Null state and is then rezz'd before the start of your next turn: they can still use their LT Special Order.