Dynamics

Right now, the font used for the dynamic marking only including the letters typically found in those markings, so you can't just replace the text without changing font. When I've seen markings like "meno f" (or, more commonly, "sempre f"), I usually see them in two different fonts. Something like ordinary Roman italics for the "meno", and the traditional larger bold script "f". So I personally would just go with that. You can override the font choices using the toolbar at the bottom of the screen while editing text. Select the word "meno" after typing it, then change its font from MScore1 to something else.

I don't find the discrepancy between the Roman italic of "meno" and the bold script of MScore1 to be problematic when used this way - like I said, it's how I usually see it. But if you wish the "meno" and "f" to use the same font, you'll have to change the whole marking to use some font other than MScore1. A quick series of checks suggests Georgia bold italic is probably the closest match to MScore1 among the commonly available fonts I have on my system. Unfortunately, the text style setting doesn't work for dynamics, so you'd have to edit all the dynamics individually. I believe you can actually customize the palettes somehow, but I've forgotten the details.

For 2.0, text styles should actually work, allwing one to easily override the default font for dynamics. But also, I recently heard that there might be a new font coming that would presumably match the characters used in the dynamics. That would be cool, too.