As I tell people in the day job Ed, it depends how the message is packaged. Constructive criticism is welcome as is encouragement when appraisal is sought on someone's work. Us mod folk don't enjoy picking up toys that have been thrown out of the pram.
Your anecdote regarding the previous Fry set-up tells us all that needs to be known about the current custodians. We know something needs to 'wash its face' as they say but it should not be to the detriment of the pieces in the collection and/or what it is meant to symbolise, hence my suggestion that the more important pieces be cared for by people who understand and appreciate their significance rather than some jobsworth who couldnt give a rats.
Anyone who took over custodianship of the collection would have to be committed to displaying it as part of a deal, not just private viewings. Anything is a lot better than it sitting in boxes somewhere in god knows what state. It wouldn't necessarily have to be Parnell Sq. either. I think experienced modellers who know just how important and delicate these models are would be the best people to look after it.
You can almost forget this find a big building in the city centre and all will be good pie in the sky. It's just not going to happen. The only place feasible would be Busaras and that was shot down by machine guns the last time it was mentioned.
Close up to confirm here http://catalogue.nli.ie/Collection/vtls000148612/Home?lookfor=&type=AllFields&filter%5B%5D=%21id%3A%22vtls000148612%22&filter%5B%5D=digitised%3A%22Digitised%22&filter%5B%5D=geographic_facet%3A%22Dublin+%28County%29%22&sort=year&page=18&view=list
As far as I know places like Bachmann and Hornby have or at least had their own draughtsman to do the design from drawings, photos etc. I believe Heljan hire in people with expertise in the loco they're modelling and get them to add their thoughts to the cad their designer draws up. Explains why the fidelity of their products is improving in the last few years.
If IE were serious about freight they could do a rebuilt on the mothballed 201s - rip out any unnecessary gear, smaller 710 engine or equivalent if required but I think I have a better chance of managing IE than that happening. It would be great to see Inchicore rebuilding locos to that extent though. Pipe dream sadly.
071s are a more versatile loco, lighter so can be used on the Taras and don't smash the track to bits. I can't say for denfinite but I would wager that a properly fettled 071 is better on fuel and more reliable, but I'm sure someone who knows better will tell me that I'm taking out of my hoop!
Other parkside kits like the 12 ton Vanwide will give you the ends as shown in Richie's second pic if you want to kitbash. Alternatively, you could buy a 2nd hand Lima, Mainline, Hornby or Bachmann van for a few quid and cut up accordingly.