Sorry to hear that she passed, it's a shame it didn't have a better ending.
If she never did lay a ooth after molting to adulthood for 15 weeks or so, she most likely succumbed to being eggbound. From my mantid logs of various species, my females on average lay their first ooth 40 days (about 6 weeks) after molting to adulthood. After their first ooth they will continue to lay another ooth typically every 1-2 weeks at most. In that regard she should have laid 5 -10 ooths in that 15 week period, of course species and individuals can vary.
According to the
Orchid mantis caresheet, they reach breeding age in 3-4 weeks after molting to adults, so the above ooth information seems to apply to your species too. In which case if you have a female that has not laid her first ooth by the 8th week at most, there is a problem. Sadly about the 9th week onward there is little that could be done to help the condition as it had already started to adversely affect her health (and likely why there was few responses to this topic). It seems your girl was a real fighter to have made it to 15 weeks.
To prevent issues like this in the future the three things that can lead to the condition are the lack of laying locations (a main issue), low humidity, and temperature issues (usually too low).
Laying locations is solved by placing more plants (artificial is fine), definitely some stick perches, and even a mesh covered lid would help. For my Carolina species I cover any females habitat lids with sticks laid loosely side by side all the way across (likely too much but they enjoy it) and one from the bottom to the lid.
For humidity just get a hydrometer and ensure the humidity level is at least 60% (for nearly all species), and up to 80% for Orchids, as said in
this other caresheet. Although high humidity without good cross ventilation (the top and side ventilated at least) can cause a mantis to die as well (see Captive Environment in
the caresheet).
Temperature wise Orchids need 72F-90F so they do need a heat source, as the optional temperature which is 82F (28C).
Regarding hot glue it drys in 5 to 45 seconds, and quite rigid in just a few minutes. I haven't heard of fumes after it is applied/leaves the glue gun, but I guess it is possible. I tend to put pets into new containers I made within an hour of finishing without any issues in over two years. The thought of fumes from hot glue has never occurred to me as I have never experienced a odor/smell or seen any problems about it before online or in my life.
So I did some more checking and can't find many details about hot glue fumes, and none once it starts to harden.
Here is one, one of the very few with any scientific data, talking about using industrial glue sticks (which are stronger adhesives) and the melt guns all day in a job setting and says, "In a nutshell, hot melt adhesives pose virtually no hazards to health when used in normal industrial practice".
Some glue sticks are also classified as non-toxic, such as Bostik hot melt glue sticks; however, of course some cheaply made glue sticks have been found to contain zinc and other trace amount additives. In which case just avoid the cheap sticks and it should be a non-issue. I did find one other pet owner (geckos) that was concerned with the odor, and
they said they wipe the cooled hot glue with a paper towel dampened with white vinegar, and once that evaporates there is no lingering odor.
