Using nn.Sequential will give you the same dict with layer names defined as ascending numbers.
Try this as a model definition and run the loop with it:
model_seq = nn.Sequential(
    nn.Linear(1, 5),
    nn.ReLU(),
    nn.Linear(5, 1),
    nn.LogSigmoid()
)

EDIT: Alternatively you could use an OrderedDict, if you need names:
from collections import OrderedDict

model_seq = nn.Sequential(OrderedDict([('fc1', nn.Linear(1, 5)),
                                       ('relu1', nn.ReLU()),
                                       ('fc2', nn.Linear(5, 1)),
                                       ('out', nn.LogSigmoid())
                                       ]))