Edward Becnel

Absolutely nothing in your explanation is a reason to queue up on day one in the middle of the night.  
 
Also,  don't make assumptions about time spent in country 

Vaccines are administered on day 2,  which doesn't affect day 1 medical process.   Showing up at 0' dark-thirty is a waste of time, unless you like standing in lines.  
 
Day 2 they give you an appointed time to return.  

It really depends. When my wife went, there was a backlog of people due to them having run out of vaccines before. First day was from 6 am until 3 pm. 2nd day was 8 am until 10 pm. If you are doing a tight schedule on the interview, showing up early may well be a good thing in case something like this happens. I understand this is not the norm, but if you have spent any real time in the Philippines. You start to understand why the Filipinos stand in lines.

I would lean toward two days after the medical, just in case of any hiccups.    Reason being the embassy requires any cancellation to be 24 hrs (or greater) before the interview, if you have an issue and can't cancel in time is when the embassy can get cranky ..  you won't be able to reschedule until the embassy resets the status.

You can have interview the next day after Medical is complete.
 
jj

My wife arrived at 10:30am and was done by 2pm the first day.  Absolutely no reason to get in line before they open 

Usem will automatically extend 

Here is an experience of another VJ'r, sorry I don't have the original link. Beware that the information is now 6 years old but I think not much has change, maybe the fee but you'll know soon enough. You'll know when you contact USEM for further information. Good luck.
 
The steps he took thinking that this might be a good step in the right direction for you. Of course, the good news this procedure you can do on your own and not involve a lawyer, thus saving you some costs.
 
The US Embassy ACS Section via email sent us the procedures on what we needed to do and a copy of the memo from the Examiner indicating that we needed DNA Testing.  They also provided a list of AABB Labs Accredited International DNA Center in the US that we can contact.
 
On 20 Oct 2013 we contacted DDC DNA Diagnostic Center Baltimore MD for Paternity Testing at http://local.dnacenter.com/DNA_Diagnostic_center_Baltimore_MD-t14355_Baltimore+MD.html and the cost for the DNA Kit was $449.  It includes three DNA Kits, cost of shipping and handling both ways (kit from USA to USEM Phil and samples from Phil SLEC back to USA DDC DNA and results to USEM from DDC DNA) and processing fee for the DNA Result.
 
On 25 Oct 2013 the US Embassy ACS Section received the DNA Kits from DDC DNA Diagnostic Center Baltimore MD.  According to the instruction memo from the ACS Section once they receive the DNA Kits they will contact St Luke’s Extension Clinic and set-up an appointment.
 
On 11 November 2013 we got an email from St Luke’s Extension Clinic indicating that our appointment was set for 5 December 2013 at 10:30AM and another appointment on the same day at US Embassy ACS Section at 12:30PM.
 
On 5 December 2013 at 10:30AM we went to St Luke’s Extension Clinic to register and pay the fee of 1,500.00 peso.  You can go there earlier which we did at 9:30AM instead of 10:30AM since it is just for registration and payment.  First you will proceed to the 4th floor and register.  Once you are done on the 4th floor you will proceed to the 5th floor and pay the fee then back to the 1st floor to fill out some forms, get digital photo and finger printed for their files.  Then you will proceed back to the 4th floor for final instructions for you next appointment at the US Embassy ACS Section.  We had to bring the following:
 ·         Your US passport or valid ID
 ·         Child’s NSO certified birth certificate (original or photocopy)
 ·         Mother’s passport or valid government ID
 ·         Drinking water for child if 3 years old and below
 ·         Two pieces 2x2 photos each with white background, if you have not yet submitted photos at the embassy at the time of your application
 On 5 December 2013 we proceeded to the US Embassy for our second appointment.  The actual DNA collection took place at the US Embassy, 2nd floor Cubicle 13 or 14 at our appointment time at 12:30PM but we had to be there 15 minutes prior by 12:15PM.  Once we were there the lady that will do the DNA testing gave all three of us a plastic cup and told us to go to the CR and gaggle five times before the test.  It took us 45 minutes to complete the DNA Testing.
Now just waiting for the final results.
This was their experience. IMHO, I would start with USEM

Exam is a two day affair (assume everything is clear) with results provided on day two to hand carry to the interview 

No issue with scheduling the interview a couple days after the medical, if all is clear vaccinations will be given on day 2 and she will hand carry the medical file to the interview.
 
https://ph.usembassy.gov/visas/immigrant-visas/fiancee-visa/the-interview/
 
http://www.visaconnection-philippines.com/k-1-visa-application.html
 
Absolutely no reason to arrive at SLEC AT 4AM let alone 2AM ...    Arrive later at SLEC (8-9-10 AM) and the "overnight" crowd has cleared saves a lot of waiting in line and you will still EASILY be done with day one.   
 
http://www.slec.ph/us-visa-applicants.shtml#clinic-hours
 
http://www.visaconnection-philippines.com/medical---slec.html