do not know re finaid but the stats for february admissions of a year or two ago showed that only 7 (seven) out of about 300 F admissions were internationals so one would think that they would welcome such an applicant. there appparently has also been talk that Midddlebury should make a push for some Asian, Australian, NZ and South American admissions to February since that time actually works well with the southern hemisphere.
Additionally it seems tht only about 25 0f 100 to 11 February admissions are early decisions, i.e. , the ones who really want the Spring admisssion and the others are those who check the box inadvertently or those who do not understand that an admission to the Spring is really for then not, not for either or to be taken off Feb for sept at waiting list time. they actually have 2 wls and if possible never the wain shall meet. they are also very defensive about the caliber of the spring admissions because there is a certain second class feel to it(no lang started in Feb, c lass choice sometimes criticized and a less than satisfactory graduation with no awards given and no real diplomas given) so they would probably bend over backwards for a science star since they have also just built an impressive new science building and pushing that part of the school.
hope that is somewhat useful. you can read some of what i told you in the archives of the campus, M's newspaper and just search february.