I got a new screen (the whole front thing) for my 6 for like 28$ on eBay and it was a breeze to replace. On the SE just be VERY careful of the TouchID cable. Otherwise you should be good.Totally. I've even starting finally using Bluetooth headphones, so I guess I could deal with no headphone jack, but the size of the new phones is killing me. I should have bought another SE when they were available last week. My SE has a broken selfie-camera lens, the touchscreen doesn't work in the corner from a drop, and Safari kills my battery life, but I'm still holding on. I tried a new iPhone and returned it in 2 days. Way too big.
iFixit has the best replacement batteries IMHO.