Currently 10k XTZ are required for baking. If me and my friends combined to have 10k, can they delegate their portion to me and I will be able to bake? Or do I need to own at least 10k myself?
As explained here
The minimum staking balance for baking is 1 roll which includes the baker plus delegated funds.
So the answer to your question is: yes
To further the minimum capital the baker need to have in order to operate on normal conditions under the current protocol (003) is the security deposit aka bond. Aspects of the calculation of the bond are detailed here