```python
from pyscf import gto, scf, fci
import numpy as np

# Task 1: Transform FCI wavefunction with respect to orbital rotation/transformation

# Molecule 1
mol1 = gto.M(atom='H 0 0 0; H 0 0 0.74', basis='sto-3g')
mf1 = scf.RHF(mol1).run()
fci1 = fci.FCI(mol1, mf1.mo_coeff)
E1, ci1 = fci1.kernel()

# Molecule 2
mol2 = gto.M(atom='H 0 0 0; H 0 0 1.48', basis='sto-3g')
mf2 = scf.RHF(mol2).run()
fci2 = fci.FCI(mol2, mf2.mo_coeff)
E2, ci2 = fci2.kernel()

# Transform wavefunction of mol1 to match mol2
mo1 = mf1.mo_coeff
mo2 = mf2.mo_coeff
ci1_transformed = fci.addons.transform_ci(ci1, mo1, mo2, mol1.nao, mol1.nelec)

# Task 2: Transfer FCI wavefunction from a smaller to a larger orbital space

# Smaller molecule
mol_small = gto.M(atom='He 0 0 0', basis='sto-3g')
mf_small = scf.RHF(mol_small).run()
fci_small = fci.FCI(mol_small, mf_small.mo_coeff)
E_small, ci_small = fci_small.kernel()

# Larger molecule (same as mol_small but with a larger basis set)
mol_large = gto.M(atom='He 0 0 0', basis='cc-pVDZ')
mf_large = scf.RHF(mol_large).run()
fci_large = fci.FCI(mol_large, mf_large.mo_coeff)
E_large, ci_large = fci_large.kernel()

# Expand wavefunction to larger orbital space
nmo_large = mf_large.mo_coeff.shape[1]
nmo_small = mf_small.mo_coeff.shape[1]
nelec = mol_small.nelectron
ci_expanded = fci.addons.enlarge_space(ci_small, nmo_small, nmo_large, nelec)

# Compare the transformed wavefunction with the one obtained from the FCI solver
print(np.allclose(ci_large, ci_expanded, atol=1e-5))

# Transform the FCI wavefunction using a different method and compare
# Here, we simply demonstrate a transformation, for example purposes
ci_transformed_different = ci_expanded  # Placeholder for an actual transformation method
print(np.allclose(ci_large, ci_transformed_different, atol=1e-5))
```