All good points. I've done space related models for years and there isn't really much about it that is different from other forms of plastic models. Only tricky bit is if one wants to get accurate, it typically means some form of scratchbuilding, or at least parts modification. It is very rare that a model can be done OOB and accurate. Although there are happy mediums in the center.
As for my cement of choice, I go with Ambroid Proweld. It is not as hot as Tenax, but it does the job in a similar fashion. Plus, right now I can acquire Proweld while Tenax is either not in production right now or worse (I work at an LHS and one distributor lists it as discontinued, no confirmation as to if that is really the case or if a new batch just hasn't been produced yet). Tamiya liquid cement is apparently similar to Tenax as well.
Filler depends on the job, but for small areas I tend to go for gap filling CA glue (usually Bob Smith IC-2000 rubber toughened CA glue, black in color so I can see what I am sanding). Large areas typically demand something stronger, so I use either Apoxie Sculpt or Milliput. I also have a couple bottles of Gunze Mr. Dissolved Putty for very light filling applications (sort of between Mr. Surfacer primer and a paint).