No idea on Sen no Rikyu, she shows up for like one scene in vol 6 with Yoshiharu, and there she was mostly just acting as an exposition character... With her being the unemotional type and the current condition of the Chinese translations, that may not be saying much though...
On Yoshiharu's lolis, I believe you guys are forgetting someone. I can't remember her name right now, but she's the person Nobuna sent Yoshiharu to visit in vol 5, the one who is the head of an all female pirate crew. She's also an S type, a ninja, can make people tell the truth by touching their head, and looks identical to the head Miko girl in Kyoto. She and Yoshiharu spends a lot of time in vol 5 together on one errand or another, so I'll count her in for the heck of it. I don't remember her showing up all that much in vol 6 though, but Yoshiharu's main companion in vol 6 is Francis, Inuchiyo, and Goemon.
On Takeda, since vol 5 ch 6 isn't done being translated, I can't be sure exactly how they managed to beat her back, but here are a few things I managed to gleam from what's out so far based on the latest translations of vol 5 and some early bits of vol 6:
Spoiler:
Let's see, I think Takeda got stalled by attacks from 3 sides (shoes on the other foot now, eh?)
First is the Mino army, under Dousan.
Second is Nobuna's army. She beat Asakura-Azai but decided against pursuing and finishing things over reinforcing Mino (and Dousan, mostly Dousan).
Third is a surprise heel face turn from a certain someone we haven't seen since vol 2.
Based on a passage from the start of vol 6, I think a certain seed that Yoshiharu planted wayp earlier has bloomed and started biting at any ass she can find, and luckily, it's Takeda's ass that's on the line this time rather than Yoshiharu's.
I am, of course, talking about Masamune. She's started her move, and her first target of attack is Takeda's territory. Therefor, Takeda was forced to retreat to defend her land from Masamune, thus leaving Mino completely safe for the time being.