I found the one I had back in the mid 1990s to be pretty hardy; the erstwhile management of Forestfarm said their seed came from one in some frost hollow of western WA that had seen very low temperatures by PNW standards. Current management of Forestfarm knows nothing about this...too bad they didn't keep better notes. And, I think this reflect a general thing going on with Forestfarm. They will still have rare plants but not someone - an owner-operator-plant-lover - going through the tedious steps to obtain the "best of all possible rare plants". (always time for a little Panglossian optimism!) I really don't think they are particularly susceptible to fungus for any reason other than having been pumped full of nitrogen to get them into fast growth...when sold as the decidedly odd looking 'mini Christmas trees'. They grow in Texas around the dry line, which certainly can be humid! Years ago someone posted a picture of some big ones in San Antonio. And also of course one grew in North Carolina. I think, south of say Richmond, VA, they are just under planted, and north of it, likely to die back in the coldest of winters.

every single one has survived almost totally unattended and Yes, I think insufficient water during that severe drought was the problem. Like I said before, I trimmed the branches and one tree still looks a little sparse but slowly filling up. Yours look a lot better than mine did during that period, you might want to let the branches be and see of the wind blows aways the black and new needles grow on the branches. Next time I go to the property I will take a pic of my ISPs and post here. They have been a joy. I try to plant one every year, taking advantage of Christmas sales, but none were to be found last year.

This might sound funny but the only mammal that eat large amounts of pine cones are Sasquatch, don't know if you have any in the far north of Texas. If you don't believe me, just watch a few youtube video's from "Colorado Bigfoot".

I agree with pretty much everything said so far. Now is a good time to repot it. Yes you should repot it, it is definitely root bound in too small of a container in container mix that is too organic (mostly peat and or bark) you should remove most or even all of it. Put it in a much larger container not just the next size up, one that is much larger. Use a container mix that is mostly coarse and mineral with little organic material (I wouldn't use a bark based soil, some bark is good but the most common ingredients should be stable, gritty, mineral particles). That way it can last for many years. Depending on your limitations, it is possible In a few years it may be difficult to do this again. Find someone in local bonsai club to help you, not to bonsai the tree, but because they will know how to do this and maybe happy to help