You don't need to do anything complicated like coin control and selecting UTXOs or Addresses if you don't care about linking all of your UTXOs together.
To consolidate, simply goto the "Send" tab in Electrum, Enter the address
from your wallet that you want to consolidate all of the coins to, then click the "max" button... then click "Pay" and sign/broadcast the transaction. All of your UTXOs will be consolidated into one.
b) I have a non-segwit wallet which always maintains a single output point. How do I prevent this from happening in my segwit wallet in the future? (i.e. maintain a single output point as well?)
I'm not sure what you mean by a "single output point"... do you mean a single address that all coins are sent to? Or a single "UTXO" that is created whenever you spend coins and get change?
Every time you receive coins, it creates a new UTXO... even if they're all in the same "address", they are all separate and unique UTXOs. The only way to maintain a single UTXO is to spend "everything", every single time you create a transaction, and receive the change back as a single UTXO. However, as soon as you receive any more coins, you're going to have multiple UTXOs again until you create another transaction that consolidates everything again.
You can do the same thing in Electrum, but it's somewhat "manual". We can simply (ab)use the "pay2many" functionally... on the "Send" tab, you simply enter the external address you are wanting to send coins to and the amount to send to that address... and then you create an entry on the 2nd line with the address from your wallet you want all the "change" to go to (as a single UTXO), and then you use
! as the payment amount, like this:
In this example, we're sending 0.1 BTC to "addressYouAreSendingCoinsTo"... and our wallet address "yourAddressForChangeUTXO" is going to receive the leftover balance (- transaction fee) as a single UTXO. After we send the transaction, we'll only have one UTXO in the wallet.