My opinion is this should have been omitted. It's none of your business how, when, or on what people spend their money on. Shaming them about it is bull@!*%.
Haven't experienced this, and hope not to, but the issue has surfaced here in the past a few times.
My opinion would be either option 1 (pull-a-part transmission) or option 3 (get it repaired professionally). Option 2 is largely throwing parts at a problem, but for all you know, option 3 could become option 2 if the shop says one of those parts is the problem and can change it without a full rebuild. Problem is option 2 may only be delaying an inevitable failure, and then you're right back at the beginning.
If you think you can rebuild yours, but you need the truck operational to bring in income, then go with option 1 and try to limp along. This would give you time to rebuild the transmission, either by yourself or professionally. Swapping the transmission isn't terrible, provided you have a bunch of extensions, some patience, and a transmission jack. There may also be a lot in savings if you pull it yourself and still have it professionally rebuilt.
Of course, if you're mechanically inclined and just happen to have an extra transmission to play with (after taking option 1), you might as well explore.