Afternoon, all

.
I need a little help, and where better to come initially than here first!
I entered into an IVA with Credtfix in June 2021 (so it's coming up to a year). The total amount of debt, as shown on the app, is £35,143.04. This is split across 8-10 creditors.
To break this down briefly, £17,081.00 of this is to Halifax (loan), £5349.00 is to Barclaycard (credit card) and £4713.00 to HSBC (credit card). So these three alone total £27,143, and come to 77% worth of the debt.
My arrangement is currently to pay £268.00 a month, with £16,080.00 currently estimated to be paid back in total (all of this shows on the Creditfix app).
My question is, first of all, am I allowed (with it being only 9 months into the IVA) to put forward an offer of a F&F?
Next, if I put forward an offer, which figure do I base it on? For instance, do I base it on paying the full amount of what I would have paid over the 5 years (so £16,080.00), or the full amount of credit owed (so £35,143.04)?
If it is the full amount of credit owed, would they expect the full £35,143.04? Or could I offer between the £16,080.00 and £35,143.04 and this would be appealing to them? For example, £20,000, or even £25,000?
Just as a FYI - I'd be looking to have a family member help me with this. That's where the money is coming from. As, despite an IVA helping me, strucute all of this, it's still affecting my mental health.
Last of all, say I did eventually have a F&F accepted and I paid it all off - am I then able to start rebuilding credit again? I know it will remain on my file for 6 years from the date I entered it, but will I still be able to start building credit again if I do pay it off earlier?
Any help is much appreciated. Thanks!