Pssible to solo Chintien as Veno?

Yes it's possible to solo TT 1-1 for a relatively low level Veno. You want to be at least level 63 because that's when your pet heal can be upgraded. I find it hard still to solo Chien at my level since that magic attack does a ton of damage to my golem. Then again, I added a lot of points to Vit so my Mag is lower than other Venos. Also, a more rounded pet with good phys and mag resists would make it easier.

The drum boss is much much easier to solo since he doesn't use his AoE in solo mode. At least he hasn't when I fought him alone.

There's a trick to get Chintien to use physical attacks, but it takes a few tries. Your pet has to attack very, very close to him, it's hard to do, but you won't have any problem with healing. If you fail, turn the camera around while spamming heal, time your run through the green explosion things before he does a 1200, 1200 combo on your pet. ><. Get to the top of the spiral thing, he won't follow you all the way up.

I just wait until he's at the back of the room, then when he's walking to the front, towards you, send pet to attack.
Then Chintien should do physical, physical, physical, physical, magic, repeat. :]