What can you do with travellers?

[DirewolfTH]

Is there any benefit befriending travellers NPC? I noticed they have no stats but do have tactics and skills.

[Huaquero]

Zuo Ci teaches you and your kids skills , Hua Tuo probably heals you . Not sure about others but yes there are pretty good benefits

[RanGa]

In the original game, they used to teach you Special Skills that can't be learnt elsewhere, not sure how it is in this game though since the Skill List has been overhauled.

[Master]

Xu Shao can help you appraise unmet free officers.
Mi Heng can help spread rumors to decrease target officer loyalty, praise officer and said officer gain better trust with you.

[FAT WANZER]

Hua Tuo heal wounds(decrease stat especialy if lose on duel,seriously zhao yun why u duel lubu)

[SirLQF]

So far from what I know that will give you effects if you are at least friendly with the Travellers and is at least an officer in a force (None of them ever visited when I played as a free officer) :
1) Zuo Ci (Hermit)
He will randomly visit you to teach you tactics/skills that you have 0 points in.
He will also come visit you once you reach a 100 in any stat to break the limit to 120.
2) Sima Hui (Master Water Mirror)
He will randomly visit you to tell you that you are doing a good job, will result in exp for skills (randomly gained).
3) Xu Shao (Face Reader)
He will randomly visit and find you an unmet free officers that are in your current city, if none is found he will just apologize and go. If he found anyone you can interact with them as if you have found them.
4) Mi Feng (Famed)
He will randomly come to you and ask about your opinion of an officer, you can generally choose the officer as if you are travelling (1 city away from your force borders). On my runs there have only been enemy officers to choose from, once you chose any that officer will have reduced loyalty.
5) Hua Tuo (God of Medicine)
Everytime you or someone you are close with get injured, he can visit and heal you up. (OP)
6) Guan Lu (Diviner)
He will randomly visit and ask you a person to read his fate, if you choose someone who is close to death Guan Lu will advise that person on what to do to prolong their lifespan.
7) Yu Ji (Hermit)
I have no idea what he does, the only clue is he will get rid of problems (?)