Without a full financial picture to include the following information:
1. Your respective incomes, with and without rental income and estimated future expenditure for each of you ( I think you have set out yours, but your husband's is unclear, what is his gross annual income from his employment and net income
2. Agreed valuations of all the properties
3. Your respective borrowing capacities
4. Costs of sale of the rental properties (estate agents and solicitor's conveyancing costs and potential GCT liability)
The circumstances of a case needs to be looked at as a whole. I can see you are trying to see if there is a way for your to remain living in the former matrimonial home, a Mesher Order is not ideal, as a husband retains a share of the matrimonial home and wife may not have enough funds in the future on a sale to buy another property, it ordered usually where there is no other alternative to provide a home for the wife and children, here you have other assets and both have a borrowing capacity.
Looking again at the figures and saying hypothetically you were to remain in the fmh,
1. Pensions are not added to liquid assets to give total assets to be divided, they are separated as they are future income.
So the fmh has an equity of £160K, the other properties total £145, your husband's debt which is accepted is a joint debt of £30 would need to come out of the proceeds of sale, that leaves £115 (less estate agent costs, solicitor's costs and potential CGT liability) how much would be left over, is it realistic for all or any of these properties to be sold, so you really need to have a clear idea of value and costs of sale and CGT liability. It may not benefit either yourself or husband for these properties to be sold as there may be little proceeds of sale dependent upon the costs of sale and CGT figures.
2. So then looking at an argument for you to stay in the matrimonial home, with you both keeping some or all of the rental properties, look at which property would have the least CGT to be paid upon sale. I do feel that at least one would need to be sold and the £30K debt repaid.
Staying in the fmh needs to be based upon realistic figures of your ability to pay mortgage and bills at the fmh. So the arguments comes back to your ability to receive an income of £2300 a month and you would need to be sure that that was an amount you could live on and an amount you would receive with your income (potentially without a rental income) benefits and
What would be left over for your husband, if he was keeping the 3 properties he already has, they would have a net equity of £187K, what about property four, in your name, what is the GCT liability etc and costs of sale. Could it repay the £30K joint debt.
If not sold then you would have £208 and your husband £187K but the £30K joint debt could not be repaid, you each have around £10K savings, so that could repay £20k of the joint debts.
Back to your ability to afford to remain living at the fmh, and getting more information as above.
Your question about whether the FMH could be transferred to you, the mortgage lender would not agree to a transfer and the release of your husband from the mortgage.
There could be many creative solutions, but without full financial information, income and borrowing capacity, tax liability, you cannot make an informed decision.