What is the size of different types of channel funding/closing transactions for the Lightning Network? This matters a lot for people who want to host a Lightning Network node and will influence LN-transaction fees, because a node-host has to justify the miner fees of setting up channels for others with the income by charging fees themselves.

If a channel-funding transaction is for example 500 bytes in size, it will often cost more than 10$. Sub-one-cent transactions through 5 channels can now only be achieved if more than 5000 transactions pass through each channel before it closes which is quite a lot.

If transactions are that funding transactions are that expensive, centralization is a major concern, because smaller users can't justify paying for 5-10 or even more channels to sustain true decentralization and will rather have one channel to a big hub.
The size of a transaction is no longer relevant. What matters is the weight (which is based on size), especially because LN uses segwit which has different weight values for segwit spends.

The expected weights for the commitment transactions and HTLC success and timeout transactions can be found here: https://github.com/lightningnetwork/lightning-rfc/blob/master/03-transactions.md#appendix-a-expected-weights.

The weight for the funding transaction is harder to know as that entirely depends on the inputs being spent and that is dependent on the sender. Since the inputs and their signatures make up the vast majority of a transaction, it is impossible to say what weight funding transactions will have as they will basically all be different.