racial mech bodies perchance? possibly some new mech parts and or weapons as well? edit: derp looks like their already there for the most part

Centasian/Avikan Hybrid Linerifle- Elemental Linerifle

There's already two new mech bodies for every race, actually, along with a new set of Avikan-themed mech legs, boosters, and a linerifle arm/weapon. More parts are definitely planned for future updates, though, including a Trinkian laser weapon and possibly some new Trinkian boosters and legs too.

A Centensian/Avikan hybrid linerifle is an interesting idea. There's two such Unique weapons (the Architect and the Errasslayer's Lance), so it's definitely possible. I was planning on adding some high-level Centensian mech parts, too.

I have the vague idea for some unique thelean scythe type weapon in the back of my head, but it might not fit into your plans :P

Actually, I had some ideas for scythe-like weapons for the Theleans myself too! I haven't quite decided what Thelean melee weapons will be yet, but scythes are definitely being considered.

Can we have a heavy linerifle for mechs? I wish it look like Metal Gear Rex's railgun

I actually have a railgun arm on my TO-DO list! It won't be quite as large as the one on Metal Gear Rex due to the way modular mech parts are configured, but it will be a bit similar.

Where can one find the item name for the remote controlled dhal? Also, can there be a seperate Fu patch to increase the spawn frequency of avian subiomes? i can find any and this prevents me from completing the monster quest.

There's a Discussions page specifically for item names/IDs, found here. You can find item names for a lot of items, NPCs, monsters etc in there. The Drahl controller's name is "drahlcontroller".

I'll look into a patch to make the wetlands biome more common with FU installed. For now, there is another option for you to get these items: all the quest items needed for those quests can be purchased from a black market vendor hidden in the Starfarer's Refuge. You can find this merchant in the pipelines on the highest floor of the Refuge. When you're in the dark corridor, look for a hatch overhead: that will take you into the pipes above.

Add the thellhunter and thell corpses in a mission

Yeah, I'm planning to add those sometime later down the line. The current plan is for all Thellhunter items to be rewards for a short custom mission, but I haven't started working on it yet.

Adding some Elithian space encounters would be nice too
Like friendly Avikan/Trinkian ships, or some Centensian ruins for anomalies

Elithian space encounters are definitely planned for future releases! I haven't really looked into how they work yet, so I'm not sure how long they'd take to build, but any new location will probably take a while to build... They are absolutely coming, though!

Due to the fact that most mini biomes have a unique coatume for them, I wonder if you could add in a costume based off of the giant sand spitter worm thingy, this will obviously need to be found in chests

I've got one. Sandspitters/sancrawlers corrupted by the Theleans. Maybe these could be found on desert planets to drop tendrils/scrap metal as well as violated droden and other such things?