Cant comment much on No.1 since i despite reading or using any form of guides.
No 2. : Personally i did little testing with smite itselfs, but it never felt good as a “main damage source” when self casted. There are nice trigger/procs though. So i would say Vengeance is better. But also don’t forget about Rive, also a very cool skill mechanically and it’s skill tree is very intersting.
No.3 : That depend on what skill you are using. With “echoes over time damage” you are refering to void damage over time or increased damage if a skill recently echoed? Both on Idols? From my experience anything damage over time related needs to be fully commited, so you either do a fully damage over time build and try to scale all the DoT’s up, or you don’t bother with DoT’s at all. Generally you need to have a good mix of “flat added” damage and % icnreases for maximum potential.
The unqiues gloves you suggested are just a low/midlevel alternative item. They have very low stats comapre to a medicore rare item. It should be very easy to find and craft a rare item that is much stronger. Especailly since Gloves have Attack or Cast Speed Affixes, which are very good for dps in almost all builds that use some kind of sustained skill.
If you are going for void damage or physical damage again depends on the skill you are going for. If all your questions in here were related to your build i am guessing you should go for Damage Over Time, Void Damage and Spell Damage
No. 4 : With my current main character, a Melee Harvest Lich i am atm at the levle 100 timeline Echoe 72, which already is very tough sometimes. My build scales very well with my weapon and i do need to find a better one to push considerably higher than that.
Havn’t dabbled in MoF with other chars yet, since i am level like 100 cahrs at the same time lol.