jeep 8.8 swap and more

So I am new to the forum and am slipping down the rabbit hole in a bad way. The dana 35 in my jeep right now is puking its guts out so its parked and cant drive it . I picked up a ford 8.8 from the junkyard and ordered an iron rock off road bracket/ truss kit for it im pretty clear on that part but what i need to know is if i lift my jeep 4" do i need an SYE, and what exactly is in my jeep. currently in college so not a lot of money to go around so tryin to prevent as much rework as possible so figured id pick some info from more experienced brains.

I am at 4 inches of lift without an SYE. Been that way for 6 months now. Every now and then I can feel a very slight driveline vibe under deceleration, but its nothing that interrupts driving or causes damage. Maybe happens once a week and my XJ is my DD.

If you weld on the spring pads so that the pinion is parallel with the output shaft of the transfer case, which you should do if not going with a slip yoke eliminator, should you later find the need for the sye you will have to shim the pinion up to point at the output shaft.

I did iro hack n tap when I did my 8.8 swap , cheap and no issues .

Dont have 4" lift yet trying to plan ahead also since im messin around with my jeep anyway thought id do something about the weld nut i broke on one of the front eye leaf spring bolts do i need to weld the nut in place or anything? been runnin it 2 years now without it welded in place and am worried about the bolt chewin up that little section of unibody as the suspension moves around am i just paranoid or has anyone seen this happening? not like it would be easy to weld the nut in place anyway