I wouldn't worry yet...could be that he is still stressed out b/c of the change. I have found that my little bloods/borneos don't deficate that often either. My adults poo every 1 1/2 months or so. I thought it was because they were large, heavy snakes that the digestion was slower. Maybe it's just the species of snake?
As for the white slimy stuff...it could be urates...hard to say...all my snakes urates are always pellets...chalky white pellets. Whether it's in the water or not. But like I said, make sure you keep your husbandry at the proper levels and soon enough you will find some poo to clean up
Just wait until it is fully grown...you'll wish that you never had the snake in the first place when you are breaking the poo up because it won't flush in the toilet because it is so big
Mike