You're making a lot of assumptions on the level of tech in BattleTech. MechWarrior neuorhelmets only translate brainwave data related to the pilot's motor cortex, cerebellum, and other balance/equilibrium functions. They don't read minds, they only translate some of the most basic brain functions to keep a 20-100 ton humanoid 'Mech upright and moving along almost like a human. All those buttons, switches, monitors, joysticks, and pedals are for controlling the BattleMech's obscene number of systems and functions, like kicking, picking up and throwing pesky Clan Elementals, walking carefully down city streets, aiming arrays of LRM-20 missile racks and supersonic Gauss rifles, calculating trajectories and firing jump-jets, etc. BattleTech's technology is meant to be more realistic compared to modern tech, so technology hasn't solved everything or even close. Artifical Intelligence in BT is not tremendously more advanced than it is now, and while it does handle things like jump-coordinate calculations, it still requires many spacers to manually operate the system and input data. Heck, BattleMechs and JumpShips and such in BT use fusion power. Not some imaginary futuristic new power source, but plain old fusion reactors, though more advanced than our own, but still quite susceptible to everything that troubles fusion systems today.
OmniMechs, artificial myomer muscles, Kearny-Fuchida jump drives, and limited cybernetics are about the extent of BattleTech's stretches on scientific realism. BT does have limited biotech, but for the most part it's not very advanced in BattleTech. The Clans have many generations of genetically-engineered warriors made exclusively from the DNA of a few hundred (IIRC) people that first traveled with Kerensky and helped found the Clans. They have Elementals and aerospace pilots that are specifically engineered for different qualities and body types. Star League lostech is not some freaky superscience, it's just moderately more advanced technology than what folks had after the Succession Wars. The Clans never lost that technology, though they didn't bring all of it with them on their Exile, so very little SL lostech is anything more than advanced versions of what the Inner Sphere still had.
BattleMechs and such communicate through systems similar to modern communication tech, though more advanced but still susceptible to being picked up by enemies, or disrupted by ECM. HyperPulse Generators send messages across space almost instantly, but only by folding space in the same way as a Jumpship, so not useable for normal communication on-planet. There's no constantly-functioning transmission network linking all machines all the time or anything, so BattleMechs couldn't be hacked into from afar. Cybernetics and biotech do get used in BattleTech to an extent, to where Clan medtechs can regrow someone's limb or even an eyeball or something, but Clan warriors are too proud and despise waste, so they won't usually allow the doctors to do that. Instead they do what Inner Sphere warriors must when losing a limb, receive a cybernetic prosthetic. It's not nearly as good as a flesh-and-blood limb, eyeball, or whatever, but it may have some minor advantage. Oh, and on the matter of 'Mech mass, it's true that the materials in BattleTech used for 'Mech construction are probably much lighter and stronger, so a 60-ton 'Mech is probably as large as three or four Abrams tanks. 'Mech weaponry in BattleTech is different from that used on small vehicles and by infantry or security forces. A BattleMech's PPC is a big freakin' particle gun that blasts cars and trucks to smoking scrap in one shot, and wreaks havoc on the electrical systems of whatever it hits. A man-pack PPC wielded by infantry may do the same to a battlearmored infantryman at best. BattleMech machine guns are on the scale for putting man-fist-sized holes in other BattleMechs and tanks, ones made with several inches of armor tougher than any titanium alloy. Infantry machine guns just put holes in people like normal, and are entirely useless against even a BattleMech's joints or ferroglass faceplate.
The MC mecha are able to do things like fly into space and tumble like a human and that sort of stuff, things out of the reach of battlemechs. If want 'mechs that can do that, though, go for it, nothing wrong with that. I just meant for a strict model of Battletech battlemechs, they'd need toned down a bit.
