No worries, just make sure you wrap the cakes properly when you freeze them so they don't get freezer burn. I'm no expert but when I've frozen cakes before I wrapped them in greaseproof paper then foil, and they came out ok. Good luck!
You can always split them then freeze, it won't make any difference before or after, that way you'd know for sure if the bigger cake was ok. You could always slice off a little tiny bit from the middle, have a taste and see if it seems ok. Then you can stop worrying!
Dense is ok, wet isn't. When you split them open to fill them you'll be able to have a prod and see what you think. Madeiras are very dense, that's why you can carve them into shapes for novelty cakes, is it a madeira you've made?
You may want to trim off some crust if it's very thick/hard. Wouldn't worry too much for a kids birthday though, they mainly eat the icing anyway!!
Just finished 2 round vanilla sponge cakes (8 and10 inches), using a recipe from a Juliet Sear book. The 8 inch has a fair crust on it and also the texture seems very dense (I haven't cut into th 10 inch). The cakes will be stacked and given a coating of vanilla syrup, marzipan and then sugar paste covering, oh and will have a buttercream filling. I'm worried about the texture though.
Any thoughts? Is it just the recipe or am I doing something wrong? I'm wondering if I should use a different recipe... It's for a children's birthday. All the other sponges I've seen at parties seem a lot lighter and more like a Victoria sponge.