I need some help with my Mod that Im making.

Your Texture? If it is OBJ model they are very finicky and hard to work with, stick with JAVA and JSON (there is no model that must be OBJ) . A custom spawning sequence? it is easy to make entities only spawn at night, in certain biomes, certain dimensions or others. As for a block spawning the entity, make a random tick update spawn {whatever the entity is) for the block (assuming it is a modded block). Also make sure to set your X, Y or Z axis to be 1 off otherwise the entity will spawn inside the block and suffocate

If that doesn't help I think you need to be a bit more specific

Models or Textures? Both are easy enough

Step 1: Export the blockbench model (java) and it will ask for a model animation definition wizard. The way this wizard works is it will animate each bone of the creature. So, you need to create bones while making the model. You should make a separate bone for each leg, arm and head. To make a bone, it is just the button next to the create cube button. Drag cubes into these bones so they are part of the bone. When you are in Mcreator with the model animator up, it will have a separate space to put an animation for each bone. Name each bone clearly so you remember which is which (legRight, armLeft, etc.). Select the appropriate animation (left legs have left leg swing animation and vice versa for right legs, arms use right/left arm swing animation, heads use head movement animation and bodies aren't animated). Select Use new animations once you finish, and you're done! The exception is spider legs, I CANNOT get them to move properly.

No problem :)