So the answer is yes, he is the only hooker.
I am sure he will play no. 9 for them. I think he came off the bench in the Tonga v Samoa game earlier in the year but I can’t remember clearly.
He has, however, been fantastic in all of the test matches for Tonga.
Tonga’s biggest problem is in the halves. Lolohea can be good on his day (a bit like Milford) but is no longer a regular first grader at the Tigers. Tonga don’t even have anyone else to pair with him. He did a decent job organising the side and showed he had a pretty good kicking game in the test against Samoa, but is the only option they have.
If you threw two top quality halves behind that pack and with those outside backs they would likely challenge Australia for No.1 in the world. Their pack in particular is incredible and they get so fired up when playing for their country (more so than I would say the Australian side does).
I was at the Tonga v Samoa game this year and the first 20 minutes of that game was the among the most brutal forward displays I have seen.