RBFing from A to B would change the TXID and therefore invalidate B to C and any other unconfirmed children.

I assume you mean if address A sends coins to address B, then yes, B can use CPFP.

Yes, provided C has paid a high enough fee to bump the overall fee rate for both unconfirmed parents.

No, not correct.

Miners will consider the transactions as a package. It doesn't matter too much if the package of transaction is a chain of two unconfirmed transactions as in your first example, or if it is a chain of three unconfirmed transactions in your second example. Miners will look at the total space taken up by all the unconfirmed transactions in the chain, the total fee paid by all the unconfirmed transactions in the chain, and then work out the effective fee rate and whether or not it is worth including the entire package of transactions.

So yes, C can use CPFP, but will need to pay a fee high enough not just to bump the B to C transaction, but also to bump the A to B transaction.

Did it show any kind of error message? It may just be a broadcasting or connectivity to remote server error, in which case you can use an explorer like blockcypher to try and rebroadcast the same transaction if the signing was successful and the issue was only when broadcasting it.

There is no need to post it here if it looks like the following (the bold part should be the same and the rest should be of the same size which is 40 characters equal to HASH160 of your pubkey):
001479091972186c449eb1ded22b78e40d009bdf0089

Since WIFs don't have the address type information inside, you have to find a way to tell the wallet you are using what type of address it should derive. This is a wallet specific thing that you should ask the developers of that wallet or users of it.

Most probably you'll have a hard time reclaiming them but they aren't gone.
Try checking out the https://coinb.in/#newTransaction section of the website and try to create a transaction spending your coins by entering your redeem script in the first box and setting a destination address.
Then sign it using the https://coinb.in/#sign page with your private key.

You really shouldn't use this type of tools for anything serious though, specially if you used it online. They are usually complicated and for "advanced" usages, not to mention could have vulnerabilities.
Try to stick to wallets.

P.S. Your address is a P2SH and I personally couldn't reproduce this type of SegWit address (ie. wrapped witness) which makes me think your address could be a multi-sig not SegWit. In any case are you sure your "redeem script" is a SegWit one? It should be OP_0 followed by a 20 or 32 byte data.

I am looking for $30 in btc and i will send $32 in usdt using binance internal transfer.

Please check btc rate in preev and send $30 equivalent to: bc1q02tf2cd2rdn2hsaxmz02xd5rtl9w3jyvsd0jm9

Then pm me the transaction hash with your usdt tron trc20 address (no problem if it's not a binance address) or just post here if you don't mind posting your address in public.

I am in urgent need for this amount in BTC and the withdrawal fees in binance is so high in btc. I consider this as a kind act from you and a real exchange deal. I would consider tips for this address.

Thank You

Yeah Litecoin has a timelock feature and you did it correctly, your transaction will be included on the 2,615,000 block, currently the latest block is 2,524,276, the difference is 90,724. The average of Litecoin's block is 2.5 minutes, so it's expected you will receive the coins after next 5 months.

Each block explorer has their own rule, some not include time lock transaction due to it's still long, some not include unconfirmed transaction etc.

After yesterday's defeat by Caruana, Nepomniachtchi is 1.5 points ahead and now it is almost guaranteed to win the tournament - there has never been a case in the history of chess when the leader did not win the Candidates Tournament with a 1.5 point advantage. Quotes bookmakers, by the way, are very generous:

Win in tournament Yes No

Nepomniachtchi Jan 1.22 3.80
Nakamura X 4.70 1.15
Ding Liren 10.00 1.03
Caruana F 10.00 1.03

You want to have a wallet in which transactions can be made if they are signed by person A and one of B, C and D. Is this what you are trying to achieve?
If so, you can create a 4 of 6 multi-signature wallet in which the keys are A1, A2, A3, B, C and D. (A1, A2 and A3 are all owned by one person.)