make sure trans fluid is topped off or change. all cv joints are greased, boots are good, and all bolts on inner are some over-tight(I think the book calls for 25lbft., i put them at 33-35lbsft.), outer axle nut is over 200ftlbs.
you should also lift or put front end on stands and i check all suspension bolts/nuts. stay at book torque for bigger bolts, and add some tightness to smaller nuts/bolts. snug calipers.
the axles are the main concern, and trans fluid level. suspension is secondary, but can be a problem, but not as likely.
if all else or you just want to do anyway; you can tighten all points on trans (not too tight its aluminum), and trans engine bell housing. you also will want to torque engine mounts, including small nuts/or bolts that hold in trans mount. maybe its time to replace mounts?.
it could be your clutch assembly, also.
swapping out both axles or all 4 cv joints sounds like a good bet too. the complete axles aren't too expensive, i found them a good investment and about the same price as all 4 cv joints.
your lash is not a good sign, and an easy cause of such noise, its probable you have/are wearing the gears, possibly the rear (unhardened side) of the gears. it doesn't matter which side, cause after a while the gap/lash can become too great and trans will wear on its self. one thing you can do is to get something magnetic, like a drain plug, something bigger will be better and use it to catch metal particles. clean every so often. the trans can last for sometime like this, i'd say change fluid, and use a magnetic piece that you can access to clean off(installed in bottom of trans).
you lose some fuel mileage, trans gears will drag some.