Any engine swap is going to be expensive when done properly. Out of your 3 choices I'm going LS all day long. All choices are going to require the transmission to be swapped and the transfer case adapted or changed. I assume the 350 is carbureted? If so IMHO that is a step backwards.
My advice is to always enjoy the jeep as is. I lost count of the number of jeeps I have bought because someone with good intentions buys a running and driving jeep and then tears it down to nuts and bolts. Then the wife gets pregnant or an unexpected bill comes up. Guess what goes first? And the bucket of bolts is worth a fraction of what you paid.
I am deep into this process - currently have engine bay gutted - stripped from firewall forward. Cleaned and painted. Installed Rocky Road SOA with High Steer kit. Should fir 35” no problem. Rebuilt 350 from 88 Corvette TBI - Hedman shorty headers - Advance Adapters enging mount kit. Plenty of information with much of it conflicting so read multiple threads before moving forward with each step. I will be using Painless wiring kit that should be here soon. Plumbing is easy once you find good diagram. Buy the FSM for the 350 and buy the FSM for the Jeep. You need the diagrams to make thing correct. Using 700r4 that was connected to 350 with SYE adapter - not cheap to do it right but this has been a blast so far
Don't do it. Or sell it and buy one with a 4.0 in it already. I wouldn't say the benefits are "tremendous". To me the 2.5 YJ and TJ call back to the era of the simple basic Jeep. Small lightweight, decent economy, ease of maintenance. Ect. Having had V8 CJs, 4.0 XJs, 4.0 and 2.5 Wranglers I wouldn't turn down a 2.5 in any of those. The 2.5 is a great little engine. All throwing a ton of power does is remove it from what it was originally intentioned to be. The 2.5 is an impressive little engine, but people want it to do what it was never meant to do. Turn big tires mostly.
