Well, have Weapon of the Web and Araneae's hand be the same Technique, and have them unlocked at level 5 if you have Silk Weaver.
For the Scorpion Whip, it's in Ultimate Combat, I'll post a link to the Scorpion Whip
Also, what about the Web grenade? could be a normal ability that is gained, or could be a technique that you get if you get the Web Hunter Advanced Technique.
Also, how about adding a feat where, when taken, you instead get another Assassin Technique, with an advanced version for Advanced Techniques.
Also, if you have camouflage at 9 ranks, wouldn't that make Child of Araneae 6 ranks? Having it at 9 ranks makes it so that, as soon as they get it, they will have the large-sized spider.
Also, for the Child of Araneae, at level 15 or level 20, have it so that it becomes upgraded to your full level, or to a level higher than 20 (as in, your Spider Blood Assassin levels count as druid levels for this Technique but with a +2).