Will FE-1 owners declare the original purchase or claim the new FE-2 market cost as a basis?Mainstream car insurance policies are designed for the pattern of use that you're describing. There's no reason to do a collector car policy on a vehicle that you're going to daily drive, it doesn't make sense for any of the parties and doesn't match the risk profile that collector car policies are designed around.
For those of us who are going to keep this as a 3rd/weekend car purely for recreational driving enjoyment in non-daily contexts, a collector car policy (with agreed value) is an ideal way protect the asset and also to save money by virtue of the extremely reduced risk profile.