If you want to use Heavy Armor (HA), go get the steed stone until you level up enough to get the conditioning perk that makes your HA weigh nothing, which requires a skill level of 70 in HA.
As for the magicka schools, Destruction, Restoration, Conjuring, Illusion, & Alteration. I would pick two, and focus on them in the beginning. Too many skills will dilute your overall effectiveness. Do a little research on the Elder Scrolls Wiki, and on here, about the different schools and make an informed choice based on your desired play style.
Conjuration can be effective as a spell blade, as the bound sword is powerful, and will increase both your Conjuration and 1 Handed skills every time. With the added bonus of it not weighing anything, can be helpful with HA. However, conjuring a bound weapon, and casting a flesh spell for raising alteration could drain your magicka pool before both can be cast. While both can last longer than it takes for your magicka to recover, without enough magicka, you won't be able to cast both. Just something to think about.
I usually don't dabble in enchanting or alchemy, I prefer to make my armor and weapons better through smithing. Plus, once you get your smithing up to level 60, you can improve enchanted weapons & armor with the Arcane Blacksmith perk. So, I cannot speak to those skills.
I would build my Spell Blade like this:
Altmer - +50 in the magicka pool is like 5 free levels, and a bonus to me that is not overcome for some time.
1 Handed
Light Armor - or Heavy Armor with the Steed Stone
Destruction - higher skills here also impact destruction enchanted weapons
Restoration - can help in not having to carry so many healing potions
Smithing
I hope that helps.