Is there a requirement to have two separate leave forms, one for PCS leave and another for PTDY?

Some units may have a local SOP, but in general, no, the PTDY is annotated in the "Remarks" block, along with the "PTDY Statement."

The reg (AR 600-8-10 Ch. 5-32) states:
"(7) Soldier is authorized to take PTDY for house hunting after written notification of PCS orders, but prior to departure on PCS.
(8) Soldier is authorized to take PTDY for house hunting en route together with leave and travel.
(9) Soldier is authorized to take PTDY for house hunting after arriving at gaining station.
(10) May be taken in increments up to the maximum authorized.
(11) Soldier must report to the gaining on-post housing office prior to starting house hunting. Failure to do so will result in Soldier being charged leave for entire period. Soldier who has unaccompanied or nonconcurrent travel entitlement OCONUS and is authorized house hunting CONUS must report to the on-post housing office at the CONUS installation where PTDY is authorized for house hunting prior to starting house hunting. Failure to do so results in Soldier being charged leave for the entire period."

Sample PTDY Statement for Block 17:
"I understand that this absence is not directed by any U.S. Government official. I further understand that I cannot conduct public business under this authorization. Accordingly, I will not be entitled to reimbursement for travel, per diem, or any other expenses. I understand that I have the right to cancel it at any time and return to my regular place of duty. PDTY _________ to __________."

(You fill in the PTDY dates, they are to be the last 10 days of the requested leave time up to the report date.)

I believe there's a disconnect will information getting to the SM, yes it can be combined on one form. Though if the Soldier does not report to the Post Housing office prior to beginning the last 10 days of hisor her authorized leave, which is in conjunction with the regular leave, he or she will be charged those ten days, regardless of them using it for house hunting. My suggestion would be to have two leave forms IOT prevent confusion among junior Soldiers.

No. You slot all of the days together and then specify in the comments block. That's what I've always done, and that's what everyone that has come in or out of all three of my past units has done.