I think the best guess for "ea" is a long E sound, like meat, neat, seat, beat, etc. Occasionally it sounds like a long A as in break, steak, and great. There's also words like permeate where the sound is a long E followed by a long A and both letters are pronounced. More on reddit.com

No, vituperat is stressed on the second syllable: viTUperat. I'd recommend listening to Johan Winge's recordings ( http://web.comhem.se/alatius/latin/ ) to get a better feel for how vowel length works with word-level stress. More on reddit.com

The Cambridge online Dictionary is good for showing both US and British pronunciation of words. This resource not only shows the pronunciation of the full word, but can provide a separate breakdown of pronunciation for the various sounds within the word. For example, I am watching the Olympics tonight, including men’s gymnastics. “Gymnastics” seemed like a good sample word for a pronunciation challenge. Here’s a link showing how the Cambridge dictionary for the word gymnastics shows how to pronounce the word. I often use Merriam Webster online for the dictionary and thesaurus. This shows alternate pronunciations also, with most pronunciations in line with my own speech patterns from the US midwest. Here’s a link to gymnastics from Merriam Webster. More on reddit.com

I mean, English orthography sucks so much in regards to pronunciation correlation that you have quite some freedom regarding correct pronunciation. And realistically, both in and out of universe people will still pronounce your words differently in different regions and social groups. If some pronounciation is important to me, I just write it in IPA symbols on a phonemic level. More on reddit.com