Can I set up a corporation while in a personal ch13 bk?

You have a number of moving parts in your plan. If you are not a shareholder in the corporation, will the 401K funds be loaned to the corporation? Or is this a situation where your "partner" is acting as a placeholder for your ownership of shares? Is the new corporation going to establish a 401K plan into which your existing funds will be invested? Who will act as plan manager and will the new corporation's stock qualify as a suitable investment? What impact will those transactions have on the Chapter 13 plan? You should consult with experienced Business, Bankruptcy, and Tax Attorneys to establish a structure to suit your goals.

Bankruptcy counsel is essential here

Your question pertains primarily to bankruptcy law. To further assist you, I am reclassifying it to the bankruptcy category, so that attorneys knowledgeable in that practice area would be more likely to see it and respond further.