Most of the questions are already covered by the previous replies.
I can see 2 addresses under Coin tab of Electrum wallet, which means I can send from only those 2, -snip-
You can send
from only those 2
Ideally how many UTXO's should you have at any one point in time in your Electrum wallet?
Is consolidating UTXO's always a good idea?
There's no ideal number since it depends on the wallet's use-case, but preferably, I'd go for lower number of coins but with high amount each so consolidation wont be necessary.
That way, Electrum wont have to use two or more UTXO when sending a transaction with high amount.
In case you received a lot transactions with small amounts like 10's of 0.00001BTC each,
all those 10 UTXO will be spent together as inputs if you want to send 0.000091BTC, each input increases the transaction's size significantly.
The higher the transaction's size, the higher the fee will be.
How do you find out when fees are low when it comes to consolidating?
Electrum has a fee estimation algorithm; "
mempool" (
based from mempool size) or "
ETA" (
default, based on Bitcoin Core's) slider.
Select mempool and slide down near the cheapest, it'll show that it's high when... it's high, low if it's low.
What's the difference between transferring and sending when it comes to UTXo's fees?
What is meant by UTXO transactions are deterministic?
I don't know either, is there any difference in "
transferring" and "
sending"?
I have no idea what you're talking about, perhaps you're mixing-up the earlier replies about "
HD wallet" and UTXO.
Please consider reading the articles in this website:
learnmeabitcoin.com/technical/ 
