You must also consider ceiling height and window size as it pertains to bedroom egress, this is separate in terms of livable space. 

The returned interest from a loan is stacking up in the account and I need to take some action to get it moving again.

I do think you need a separate entrance option or at least two entrances in a four-plex to make it easier on the LTR tenants, but if you are open about it form the start, everyone gets it and you choose the unit composition based on which ones will be STR or MTR.

How long do they sit on the market, are you finding them in move-in-ready condition, or will they need work before you move in? 

@David R Pustelnik recommend you first focus on raising the rent for the first time in 10 years.By the way, how much have your property taxes and home insurance gone up since this tenant moved in?

They had a search set-up for multi-family and for any single family homes with 4+ bedrooms to see if there were any possibilities of creating a separate living space.

My lease has a sublet fee (2 weeks is guest by lease more than 2 weeks in a year is sublet) that is costly enough ($100/night per person which is about what a cheaper hotel is here) that makes sure tenants do not have others move-in without informing us.

If you continue filing taxes jointly the income you realize from your separate property will still need to be explained and redacted, regardless of the type of entity holding the real estate.

I also want to combine it to one $150k  30 year fixed loan instead of having two separate  $100k and $50k loans what options do I have can anyone help.I don't want to use my own money.

You are on a great trajectory and learning curve because you are learning from your mistakes and also preparing to move slowly instead of scaling before you are ready.