The other commenters are right that your scores are pretty decent. On the other hand I do understand your concern. If I were you I would feel like my scores are borderline too and would be looking to get them up.
For one thing, I seem to remember some forum contributors with more mortgage expertise than I have once observing that the FICO thresholds for being gold-plated are different depending on whether one is talking about the loan itself or whether one is talking about the PMI for the loan. You sometimes need a higher score for best rates on PMI -- or so I was told.
As far as removing finance company accounts, the same rule applies as it would to any account, which is that the creditor itself has a lot of discretionary power to delete any account it chooses. That's why people are able to negotiate "pay for delete" agreements -- strictly speaking, you'd think that such agreements would be impossible, since it should not be possible (one could argue) for a creditor to remove accurate data from a consumer's report. But in fact they can. So it is possible that you could get any particular finance company account deleted if you could get a sympathetic creditor (cry a little bit, explain how it is showing as an FC account, how there was no way to know that, how this could devastate your home owning future, etc.).
On the other hand, it's also possible that, for FICO "too many" (as in "too many FC accounts") means "1 or more." Thus unless you were able to get ALL of them deleted (not likely) you might not experience much benefit.
You raise an interesting question which is whether FICO views a closed FC account as less of a problem than an open one. (Possibly still a problem but less of one.) I do not know I have heard anyone answer that definitively (i.e. with clear references to FICO literature or test results).
What is your timeline for buying a house? Do you have any other ways you could improve your score? For example, are all your cards at $0 except one showing a fairly small positive balance? (That will help a lot.) Do you have any open installment loans? If not, we can suggest a simple strategy to help in that area too.
When you say that your "score" is 755, are you sure that is your mortgage score? There are many FICO scores that are not the ones mortgage lenders use. For example, the very common FICO 8 score is not used by mortgage lenders. If the score is a true mortgage score, do you have a mortgage score from each CRA?
