Blathers

Thanks everyone for the insight! I'll definitely check out the All Japan Filers thread as well.
 
After periodically checking the Tokyo embassy site and reading what other people have experienced, it does look like dates periodically open up, but with no real rhyme or reason which dates become available. When we finally saw a calendar displayed, only one day was open on September 17. We haven't filed for the medical exam, so we weren't able to grab that date, but hoping for the best for something towards the end of the year.

My fiance was able to get in today! She doesn't speak much English, so she was pulled into a separate room after being unable to answer a few questions. She had my contact information, so customs called me up momentarily afterwards. I'm sure it's obviously different per situation, but here's what they asked for reference:
Why are you visiting? Why are you staying for so long? When was the last time you were in the states and for how long? What does your fiance do? Where did you two meet? How far are you in the K1 visa process? Hope this helps! Hit me up if you have any other questions that I might potentially have answers to.

My fiance was able to get in today! She doesn't speak much English, so she was pulled into a separate room after being unable to answer a few questions. She had my contact information, so customs called me up momentarily afterwards. I'm sure it's obviously different per situation, but here's what they asked for reference:
Why are you visiting? Why are you staying for so long? When was the last time you were in the states and for how long? What does your fiance do? Where did you two meet? How far are you in the K1 visa process? Hope this helps! Hit me up if you have any other questions that I might potentially have answers to.

This is a pinned item at the top of the k1 forum (see below).

To summarize, you're unlikely to have any problems traveling on ESTA while you have a k1 in process. Usual provisions apply as for any tourist visit - be prepared to show good ties to home, long trips and frequent trips are likely to result in more indepth questioning by CBP agent, don't carry anything that shows intention to stay permanently (too much luggage, resume/CV, etc, birth certificate).
 
Even if entry was denied, it won't affect future k1 unless lies were told. So be truthful - you don't have offer up that you're seeing fiance if they don't ask, but if they ask who you are visiting/staying with then be honest (don't say "a friend"). But as you'll see from the thread very few have had issues (I traveled 2 or 3 times after applying for k1 with no problems)
 
 
 

My husband (then fiance) had a B visa, and visited while our I-129F petition approval was pending.  He was just completely honest at POE, and had evidence of loose ties back home in NZ that he had to return to take care of before he could immigrate.

That is false.....it would not jeopardize the K-1......although every entry is at the discretion of CBP at the time of entry.  She should be truthful and she should be prepared to show evidence of strong ties to her country.  It is her responsibility to convince CBP that she will return at the end of her visit.  Worst case would a denial of entry and immediate return. 

She absolutely can visit on the VWP whilst you wait. Her entry isn’t guaranteed, but no entry for visitors is ever guaranteed anyway. It will be at the discretion of the CBP Officer at the airport but having a pending I-129F is no barrier to visiting.