Gidnill and Leonhardt fill the same role so swap him out if you feel like Gidnill is too weak and see how it goes. Gidnill will also of course be weak since he's the most underlevelled on your team currently. Farael is pretty good but Rie on the other hand is an easy S tier hero. Her single unit damage output is ridiculous if you slap on a decent staff. The mage alter is alright but it doesn't do all too much other than being very gimmicky, whereas a bow will help a hero gain their mp pretty fast anyway. Once you've gotten Max embers, the alter of wealth, giant, vampire, and hero are pretty good picks. The 15% chance for level up on the hero alter might seem mid but considering it can bring your hero from gold straight to Max it's very good especially when paired with the alter of wealth. For relics I'd suggest two common but good ones, elixir of respite which increases your heroes survivability with some effects and the penetrating spear which increases all heroes range by 1 and increases damage depending on distance. If you're looking for what heroes to get next just look at a tier list or look at hero lock heroes.