Just missed the GM by an hour from the looks of it...
- For no.1 There's only been one proper engagement in the manga that involved mental models... Essentially expect barrier based combat and local gravity shift shenanigans... However the ship/character is still able to utilize the equipment present on their ship body... So for example the ship body might be out on the harbor and situation dictates the need for offshore bombardment support on the Mental Model's position then that's perfectly within their capabilities...
- For no.2 That's the part that you solve by hiding the ships... Because if anything the 80 or so chapters of the manga has shown, is that the FOG vessels are extremely good at hiding, submarine or not...
- And as for the last part... I'm just not entirely sure how the things in Kancolle work in general I mean paper talismans turning into miniature warplanes complete with pilots, I'd chuck that one as magic but I don't know if it is canonically actually magic... Yes I should be able to roleplay them fine since I have made fanfics for it but what I'm worried about is that I might portray how things work in a completely inaccurate manner...
If you're fine with it being slightly AU then yes Kancolle is a second choice...
The people in select serieses/universes who would take notice of an Artificial intelligence, reconfigurable warship armed with graviton and photon weapons and composed of nanomaterials would also very likely also take notice of a girl that can induce localized gravitational anomalies and project barriers impervious to conventional weaponry and also made out of nanomaterials...
Though at least they eat normal food...
Instead of munching on mortar shells, aluminum ore and washing it down with black gold... Oh and then eating normal food...
While that's going on I've decided that the backup plan of Kancolle, should I use characters from said universe I would opt for original ship girls or at least ship girl forms of vessels in WWII which have yet to appear in the kancolle franchise to give me a bit more leeway in explaining how things work... Though of course this would mean I'd have no picture of said ship girls and such will go against your prediction of such part always being a picture... Could always go the VitaVita route and draw em myself... But that would mean going through the horrors of actually drawing...
And that there is why I would preferably have the ship body included... Deterrence, It's better to have it and not need it than need it and not have it...