Yea, then the healing times I suggested should work for you (assuming you will separate the duo)
Good call on the cray, you see those should really be kept in a species tank, with lots of caves and substrate to dig around in. multiple crays can be kept together in a large tank, but no cray should be housed in less than a 10-15 gallon tank
As for the pair of Betta, I will say that I've seen such occurrences but only in HUGE tanks. where the female can hide from the male. in such a small tank I cannot see how it will work (I've bred Betta before and am quite familiar with their aggressive nature)
Their first impression together can be quite decieving! One day they may be all "^__^" while the next day you may find one curled up and dead, floating in the current, and the other badly bruised...
Male and Female Betta should NOT be kept together unless you breed them, and then again only when they've gone through conditioning and in a proper tank set-up...
Otherwise you're asking for trouble and dead/sick fish...I cannot stress this enough