Oops totally didn't respond to this. Four scarabs, yeah. No skulls. As for the sword thing, you can choose not to level the sword up I suppose...not sure how the skill system works with the story though since you get Jinran Maru and Blade of the Archfiend in cutscenes. Guess we'll see, but my guess is that your sword will look like whatever the highest sword level you bought looks like.
I thought that the single sword style progression was locked to the story, seeing as you would probably need the BotA for the Underworld Drop but I never played the actual game, just watched stuff on youtube.
Speaking of leveling the swords, I (think I) faced a glitch the other day, a good glitch nonetheless but I'm 100% sure my eyes did not fool me. The demo limits you to lvl 2 weapons and I'd suppose that it limits your UT depending on the lvl... but I shit you not it did the lvl 3 UT for me when I went do it with the dual katanas.
It was funny too because I'd seen it a million times in videos but I activated the UT (from bloody rage, no idea what multiplier) and I went to slide after the second wind slash, but he just crossed his arms and let the 3rd one fly... I couldn't believe it... I just hope I wasn't trippin.
If it happens again, I'll definitely catch it and see if there's certain credentials. Otherwise... I don't know.