at 450k, i think you did just fine selling the PF. Someone else made a bit of an impulse buy on someone probably worth 350k based on his vitals.
Again, i'm not the expert in training, but i fancy myself as good at putting together a roster. I'd cut Xiao and TL the Lampis and Levente. Levente has too little potential, so he won't really develop. He's just not worth spending 2-3 seasons on because he'll cap out in development and leave you with a good D.V or D.IV player, but someone that wont help you going forward when you aspire to get up to D.III.
Even as a new GM, you have a good shot to get out of the relegation in D.IV based on not only your side of the league, but the league as a whole amongst relegation teams. The 6th place team on the other side is pretty nasty, but the 7th place team over there, and the 5th and 7th place teams on your side are all potentially winnable games. Keep looking for the right price on a player that is a few years south of 32, and you should be able to build your arena and team around the talent you are developing now.