Thank you Piotrek1, Whiskey_Sierra 972 and Hubberranz for your advice and help.
Sorry for the lack of response for so long time, but I've been busy with other things and haven't had time to deal with IL-2.
...CTD at 70% stationaries are wrong. You possibly had an other version and older stationaries entries may still be in there.
Review all lines in your stationary.ini for all ships entries. Likewise revise technic.ini for no lingering past entries.
If you suppress all stationaries of this mod and any previous ones temporarily, you can check if the ships by themselves do work. ...and Iowa showed up on the FMB Ships list and on the map...but on the Stationary Ships list they are visible in the preview but I'm not able to add them to the map...
Still , static class files conflict are possible; mods are use first, sfs are superseded by mods. However I have experienced class conflict at times even when loadings are properly ordered. Happens.
I'm Not using VP pack. I use 412.2 SAS5.3 with this "IOWA sfs mod" for a long while.
(..its good policy while testing new mods to go for the stationnaries separately and at the very last after the mods are proven to work first and foremost whitout the stationaries active yet ).
Hope this helps.
PS: ...when removing/replacing a mod, active stationaries pointing to the original mod will CTD the game.
"Review all lines in your stationary.ini for all ships entries. Likewise revise technic.ini for no lingering past entries." - yes, I do this every time I add/remove a new object (plane or ship) and I did it the same this time.
Thinking that other mods might be conflicting with Iowa_pack in my most advanced modded version of VP in years, I installed fresh clean installs of VP modpack over fresh install of 4.12.2 with no new mods.
I added then only the Iowa_Pack v1.1 and with result - Iowa familly ships showed up on the FMB Ships list and on the map, but on the Stationary Ships list they are still only visible in the preview but I'm not able to add them to the map...
As for the advanced modded version of my VP, when using suggestions from western0221:
"When you faces 70% CTD in installing The Radge's Iowa pack, that may be caused by classfiles conflict with old Diving_Hawks ones. Then , disable "Ship_JFC_Classes" folder with renaming to "-Ship_JFC_Classes" (adding - before the name letters)."- when I disable/remove the Ship_JFC_Classes it will work for the Iowa_Pack, but again only partially - in FMB they appear as Ships but not as Stationary Ships - identically as in the completely fresh unmodded version of VP modpack. Also unfortunately, downside to this is that the battleship Yamato, which shares the same Ship_JFC_Classes doesn't work either without them in VP.
So in summary from all of my experience:
1) Iowa_pack v1.1 conflicts with Ship_JFC_Classes as stated before, so you have to choose whether Diving_Hawks single Iowa and Yamato OR Iowa_pack.
2) Iowa_pack v1.1 works on fresh unmodded version of VP modack - but only in Ships section and not in Stationary ships.
3) I still don't know what else I can do, to make Iowa-pack v1.1 work fully (Ships and Stationary ship) in VP Modpack?... :/