Firstly, dont worry too much. I know it is easy to say but break things downand combat them one at a time...
1. I think he is barking for attention. He probably is a spolit little cocker. Cockers always try to get what they want. Ignore him when he barks - make this a rule! When he is calm and not barking praise him verbally and give him high value treats ie chicken.
2. toilet training - leave him outside for longer. Keep up praising him when he does go outside - keep at it. Suddenly it will work and you will wonder why you worried. Just keep pointing him to the right place, when he goes say toilet - he will then associate action of toilet with the word. praise verbally and with treat. patience is required, plus remain calm.
3. recall is hard - maybe use a training long line - let him go off onthe line - call him, nudge him back to you with the line and treat! lots and lots of practise.
4. leave it command - when he has something give a command ie leave and try and EXCHANGE what he has - ie give him a toy or treat.
Once you have the basics under control you can fade away treats and give more verbal praise and pats.
Dont worry he is young and all pups develop at different rates. It could be made a little worse if you have slighly spoilt him. Put your foot down gently and really reward all his good behaviour when he does do it!
Maybe you could go to a local training class for help, support and you will also realise that others are having the same problems but maybe with dogs or are 4 or 5 ! and are only just getting themself to a class.
I hope this helps and best of luck..
ps my 10 month old cocker did a wee on my bed the other day!!!! i thought she was completely trained at 12 weeks - but sometimes a little relapse happens. After having 2 cockers I have realised not to stress but take it as it comes and try and be positive