R12.1.1 : Need Confirmation for Patch Application in Node2 Application(Oracle Applications with RAC

Hello,

We have RAC DB(11.1.0.7) with Oracle Applications E-Biz Suite Release 12.1.1.
RAC DB with ip xxx.xx.xxx.26 and xxx.xx.xxx.27
Two Application Nodes xxx.xx.xxx.28 and xxx.xx.xxx.20

We need to confirm the following related to Patch Application:

1. Should we apply the patch in application node2(20) after successfully applying it in Node1? Kindly suggest a note id if available.
2. If yes, Is it required to stop node1(28) after patch applied,  while applying the same in node2 ?
3. Suppose the patch applied in node1 did some DB level changes, will the same changes be done again while applying in node2 ?