A 12" Scolopendra heros would be quite large for the species. But Hadrurus arizonensis is on the bigger side for scorpions, Some large Orthoptera around as well.
Hierodula sp. java hasn't been described yet, which is why you haven't heard the full scientific name. They'll probably stay a bit smaller than majuscula and such.
Rhombodera megaera and Hierodula majuscula rival most in culture currently. Cilnia humeralis is probably the bulkiest but isn't really in culture right now.
Something happened during the process which made it take unusually long. Once it warms up a little more in a couple weeks he'll send replacements is what I've been told.
Lucky you found her in time. I was going to say right as I was reading the first part that it sounds like she's about to moult, but then you figured that out haha.
If you were to buy 10 unsexed nymphs, there's no way you can know how many are going to be of each sex lol. You can only find out once they're sexable. And I don't believe any species produces higher percentages of one sex than of the other, it's rather random.
Most females will lay multiple ooths whether you mate them or not. If she's not mated they just won't be fertile, with the exception of parthenogenetic species.
I've heard people say once a week or so before she lays. And then after she lays. One mating should be enough for a couple ooths, but fertility will start to decrease after a few oothecae are laid.