Can I use a combination of pension and bank deposit to meet the 800,000 THB requirement for my visa in Thailand?

I'm with all of the above

As advised, speak to the local immigration for what they will/can accept, many that will accept monthly transfers want to see them happening over 1 year, not in big chunks and if your using wise I believe there is a proper reason code to choose, something like long term stay in a foreign country, I do know it's important to use the right code for it to be accepted, also if your local immigration do want the 800k in the bank check how long before and after the visa application they need to see it still, most I think want it in bank 2 months before and 2 months after, and also check if your allowed to use some if required, some say no must remain 800k for life of visa and some allowance down to 400k but must go back to 800k before renewal

You would have to ask the Office you are applying to. Some accept a combination some don't.

You would need to check with your immigration office. Some accept combination method, some do not.

But unless your embassy issues income verification (many do not), you cannot use your pension for the first year. You would only be able to use 800,000 in the bank.