I am not 100% sure of what is true.

1.  I am under the impression that there is no transfer paperwork required between immediate family members if they are blood relatives.  (immediate is brother, sister, mother, father)

2.  Does this extend further i.e. grandparents?  Or even further i.e. cousins?

3.  What about husband and wife?  I believe it is almost considered joint ownership, i.e. we can use/carry each other's guns freely but is a bonafide gift from husband to wife legal without a dealer transfer?

You can avoid the transfer process if you are immediately related such as spouse, child, grandchild, parent, or grandparent. If you are a cousin, aunt, uncle, or unmarried partner, or friend you must transfer the gun through a dealer. Long arms such as rifles and shotguns do not need to be transferred through a dealer as long as you know that the person is a legal resident of PA is not restricted persons under PA Statute Title 18  § 6105 - Persons not to possess, use, manufacture, control, sell or transfer firearms.

PA Title 18 § 6105

No transfer needed between spouses, parents and children, grandparents and grandchildren.

Transfer is required between siblings (brothers and sisters).

There is no requirement that a firearm be in a persons name for them to carry it, as there is no registration in PA. But, my wife can carry or be in possession of any firearm I bought, and vice versa.

Any person who would receive the firearm, must not be a prohibited person and live in PA, along with the person giving them the firearm.

Whats the point of transfing if there is no registration in PA.  They would has to have some kind of registration  somewhere to known its not your pistol

It’s a “database of transfers”, not a registry because it only includes handgun transfers done thru FFL’s (PA form SP-1, in addition to 4473 needs to be filled out. It’s bascially the same as 4473 but also asks your profession), not long gun sales either thru an FFL or privately, or any weapons brought in from out of state.
The PA Uniform Firearms Act states SP-1’s must be destroyed after a length of time (72 hours I believe), and that no registry can be created or maintained. However the PSP electronically record and keep the info before destroying the forms - and this BS was ruled legal by the PA superior court.

Also, a lot of people don’t realize that the FFL does not do a background check thru NICS in PA.
The check goes thru PICS, which accesses NICS, and there is a $2 fee, plus $3 per taxable item.
IMO, this is more stupidity that is unique to PA.

So if you sold the pistol online they would still think you had it?

I believe so. I don’t think they ever change the info in the “database that’s not a registry”.
If it changes hands in PA, every new owner would show up, unless the transfer was between spouses, parent to child or grandparent to grandchild or vice versa, unless they chose to do the transfer via FFL for whatever reason.

Because the law requires that firearms be transferred with a few limited exceptions. And I use the term firearm as defined in 18 PA.C.S. 6102.