Probably not. But as it is a byproduct some sort of amendment may be made in the future to capture the value.
At this time, I believe it is not the PPSA we are waiting on to be signed but the amendments to the Petroleum Act that need to pass parliament. Once the amendments to the Petroleum Act are passed there will likely be some additional time required to actually finalize the PPSA.
If Helium was the primary resource, it may be very different. I think HE1's & NHE's acreages in Tanzania only gives them the rights to the Helium. If they find gas, then they don't have title to it.
As to your second question regarding majors and the PPSA, if they wanted a say they have had the opportunity to do a deal with IVZ. But there is still a lot to be done before any production and that is getting approval for the development. As in Australia there, there will be a bunch of approvals EPA, etc from various parties before a production licence will be granted.
At this time there may be some amendments made specific to the project to be developed. This would also be where production of helium could be addressed.
