Thiago Silva is a good CB i've picked him up a few times for well under 6 million in the first season but 2nd season im not sure what he would set you back but worth a look.
Depending on who went down you might beable to pick up a decent little CB from one of those 3 teams, Alot of them will hand in transfer requests which gives you a good chance to pick up a real bargain.Even if its only until next season when you have abit more cash to spend anyone you pick up will beable to be sold off for a nice profit the following season anyway.
LB the best option is Joe Mattock without a doubt, Even in the 2nd season he will be cheap and hes one of the best LB's in the game for years to come.No doubt his price will have gone up alittle from the first season but still he wont be that much.