Possible Transfer??

I got a call from the HR department in Tokyo. They said they "may" have a position open for me. Since my Japanese is only at "conversational" level, I would be placed in the back end to handle the systems. But eventually, since the project is client heavy interfacing, I would have to beef up my Japanese. I told them that given the opportunity I would excel in Japanese and the position. They told me to expect a phone call from a few engineers later this week. Our conversation was nice. The main guy, I spoke with seemed energetic and cheerful. This is a good sign especially since they called me at 3:30AM Tokyo Time. Yeah.. they work late, but on the plus side they told me if I work really late one night, I would get compensated the next day and so on. The one major drawback so far is that they are looking at a target date of mid to late May of me starting if I were a fit to the team. This may cause a potential problem with me since I had everything planned out to move in mid June. I don't mind visiting Tokyo for a week or two to finalize everything on the job front and find some housing, but I also need time to finalize everything here in the states. Especially since my intentions are to leave here permanently. I also need to go to CA for a wedding on June 1st. I promised my friend I would not miss it. I discussed my conversation with my manager and he said to wait and see before we start thinking about time lines. Anyways, I will update more once I get contact from the engineers.