Lol. I can't say anything about the first, but Yuhao can absorb spirit rings the "normal" way. He absorbs 6/7 (I don't know if I can count the last one as a spirit ring or a spirit :x) spirits that stay with him. Since they all have conscious minds, the limit to how many spirits a body can possess is limited to how many ring spaces you have (regular people can only have up to 9 spirit rings-titled doulao- and twin spirit users can have double that) and if the spirits can coexist together. :)
He also has an unknown spirit that entered him the same time as that thousand yo worm and in the next chapter the spirit takes control of Yuhao's body and brain damages the Red Dragon Girl, hes eyes turn grey too and the girl sees the Death Reaper above Yuhao and black feathers fall around them...so far the spirit has no shape, it's just a grey glow and I don't know if it's good or bad character :( ...in 40s chapter he will get his second spirit to be with that worm....that makes two spirit rings and 3 spirits with their own personalities all that in his head...
Oh, him. He is a spirit, but he's not from this world. If you've read Shen Yin Wang Zuo, the spirit is Electrolux (necromancer/scion of light). His soul fragmented and dispersed to different worlds. The effect is that Yuhao essentially has a third soul spirit and ability. He doesn't add rings to it though (I don't know if it's because he can't or if it would just be too OP :P).
There are two things I don't like about Doulou Dalu II 1) is that later updates show Tang San adult version before Doulou Dalu I and 2) the way Yuhao absorbs spirit rings...I mean how many spirits can a single body possess??? ┑(￣Д ￣)┍