Hi, my thoughts, well, more guesses than anything so dont take them too seriously would be:
I saw a photo of a barn which if i remember correctly you would make into a house? Have a dig down yourself and see if it has proper foundations, won't cost anything and would be a conversation opener with engineer.
The planners might say you have to "do up" the end of your driveway, put in visibility splays and tarmac/kerb them to a certain standard, cost? Probably a lot of £s
If i was starting from scratch i'd put in a drive through disinfection "pit" in my gateway, as per FMD days.
Security cameras fitted to the entrance, yard and house. Mains electric fencing on the boundaries, i'd like it low down enough to give foxes and badgers a kick too.
I don't thing you'll need planning for the static while you're building with planning permission, cost, possibly £0
Are mains services already installed? Cost, £0 to £Lots
Storeage for things from your house till new house is ready, anywhere dry and secure or would a shipping container be better/safer.
How about two caravans, one for day living and one for sleeping?
Fencing, landscaping, then of course housing for stock, medicine cabinets, feed store, isolation unit, trailer storage.
Whatever you decide to do, i wouldn't rush into putting any permanent structures up until you've lived there for at least a year and have found out where the sun shines most, the frost pockets are, wet patches appear etc, i've had my latest place for two years and am only just working out the best places for everything!
Best of luck, look forward to the photos, if you want any practice fencing etc let me know!