Would work fine by the inch per gallon GUIDELINE but, you see, that's just it - it's only a guideline.
Hatchetfish are prone to being bullied - both the rainbows and angels are likely to bully them - the angels to a greater extent. Angels, hatchets and gouramies all occupy the same sort of upper-middle areas in the tank, they won't appreciate being kept together. If the angels pair up, they may even get violent towards these fish. BTW, boesmani rainbows don't get to 2", they get to 4" (3.5" or so is usual). 4 also isn't a large enough shoal as rainbows tend to be nervous fish when kept in inadequately-sized groups and won't get on that well. You also have an issue with the platies - possibly - as they should either be kept as a trio (1 male with 2 or more females) or in single-sex groups where a group of 3 or more is best if what you want to keep is males. Also consider that panda cories are one of the more fragile cories and may not do particularly well if the angels breed and decide to pick on them. BTW, do you want a pair of angels? You can't sex them visualy - not as juveniles anyway - so you'd need a group of 4-6 and then to let them pair off, returning the excess to your LFS.
What I suggest you do is skip the hatchets, increase the number of rainbows to 6 and then determine whether you want that pair of angels to breed or not. If you do, get 6 juveniles and skip the panda cories (though you could try a hardier type like bronze/albino, peppered or blackfin if you want). Once a couple pair off, return the rest to your LFS. If you don't care if they breed (though there's no guarantee they won't), I'd risk the pandas if you realy want them but sip the platies as, with the 6 rainbows, you'd have quite a lot of fish in there anyway.