I think you may have outgeared yourself (5.13s) with the 4.5bp. Biggest limitation is the 4.5bp. It limits the hub/spindle diameter for any acceptable bearing size for a front axle. You are sort of working backwards to get a matching set of axles.
Cheapest would be to sell the 8.8, look for matching axles to work with a set of matching r&ps.
Probably the cheapest option of getting a front axle to match the 8.8 in the rear with the 5.13, is to figure a D44 front axle (low or high pinion), then match a set of wheels for it, then match a conversion spacer on the 8.8 to match the wheels. If you can locate a Rubicon TJ D44 housing, then you could add the 5.13s and swap over your TJD30 stuff. But that can add up initially but nickle/dimes won't hurt you with the D30 swap stuff.
A front D44 can come from a 80s Wagoneer for a low pinion or late 70s Ford for a high pinion. 5.13 would be available for either. Wagoneer would be wider than stock mws but not by much. It was SUA leaf mount but there should be enough axle tube on driver's side to add a link setup. Ford front, you could actually modify to make it Wagoneer wide with shortening one side for a stock inner shaft. You would probably want a F250 D44RHD (3/4ton) where the tubes are 1/2" wall thick and axle is leaf mounted. Plenty of axle tube surface for mounting a link suspension. If you find a 1/2ton front, don't be disappointed. The tubes are thinner walled, axle tubes are not continuous, and the cast wedges are welded to the tubes but figure they were bolted into Broncos that weighed nearly 6k#s or more. Suspension setup will include a radius arm design (axle 'C' cups). Duffy and Cage both provide long radius arm setups with large heims for the Ford radius arm design suspensio. Or you could build your own.
Nikcle/diming can hurt here with brakes, tie rod ends, track bar setup, suspension setup, etc.
Not many other options out there to make a front axle to match a 5.13 geared rear axle with a 4.5bp.
