I will try to respond to some of your questions but have to caveat that my knowledge is probably old and out of date. There was a recent patch which reduced mob health significantly but the problem with PVE in general is we dont actually know any numbers. The best real advice I can give you is test it for yourself and see what feels right.

I realise this not the answer you wanted so I will give you a bit of insight into why I say it. The whole thing depends on what you want to do with the char other than farm warbots. If you want to pvp then you need to spec resists. If you have an LE in and want to build a dedicated farmer then thats easy.

All you need is a pulse laser rifle/laser rifle (insert preference) and a heavy energy protection belt - TH vendor last time I played.

Hacking - 50+ provided you have loot rights you should get favourable results in the hacking game. I have heard people do it with less than 50 hack (as low as 40) but truthfully as a spy you have tonnes of int, so why would you make life harder on yourself.

In terms of range, if they can see you they can shoot you. It seems this way with all mobs. Kiting can be fun but if you back into another group as a spy its going to be difficult to survive. You need to be more sneaky.

Terrain/geography - there arent too many "sniping" spots in NC unfortunately and you will need to go down and hack the corpses anyway so anywhere you go up high is going to be tough to get back to without your glider and if youre killing multiple bots at once you need to be straight in there to hack them asap after.

Resists = more energy is better. The force damage comes from the rockets (like the launcher cyclops fires) and if you can avoid these you dont need to worry too much about force resist. If the odd one catches you then make sure you can heal through it but understand this will limit the amount of transport you have.

Everything in this game is built around ratios. The higher tech combat and weapon lore you have the more damage you will do which will mean theoretically the less health you need to survive the hits they dish out to you. The more damage you can put out in a short space of time the better, with the new mob health changes this will become even more apparent. Your survivability has already gone up just because their health went down.

All of the above is based on "old" experience of playing the game. Some may not be completely relevant today.

As for hoverbots - historically over 80-90 hack was recommended but nobody hunted them because their hit box could/would get stuck on trees and it became a pain in the rear to hack them. You got the same drop rate as warbots for the most part and so because they were easier to hunt the vast majority of players used to go for warbots instead. Occasionally you would see people have a go with the hovers for variety, not sure if thats still the case. It is different now that there are hoverbot trophies etc to collect but again due to current PVE being more difficult than historically I do not know relevant this information is.

Crahn armour is recommended for the energy resist, although it is only a small amount - compare it to Kevlar 3/battle vest 3 and see if the energy you gain is worth the force you lost from the other, or wear a mix obviously.

Resist drugs - i dislike drug flash, especially as you know murphys law says you will run into someone aggressive the minute you get a DF.

Fire mobs - fire rapes spies. There is no way around it. Years ago I experimented with using as many strength imps as I could to get up to INQ 1 levels of fire resist (45-49 str) as a spy to try to cap out my first char. However I found that all I was doing was turning it into a PE who had no psi. I quickly gave up.

In modern times I honestly have no idea how spies will match up to grim chasers, i suspect badly considering many tank players have trouble with them but again I would say perfect your strategy with warbotting and go from there. Mob AI is much the same, its just the damage they hit you with that will make things end faster.

Unfortunately PVE is difficult to balance and a very different beast from pvp. If you make it too easy for spies then tanks will have a field day and if you make it difficult for tanks then spies will be non-existant. It is due to mob AI/damage/resists etc. I know work is ongoing to even out this issue but I think it depends on the individual and what they want out of it to honestly give an accurate conclusion.

In short: If you want to play a spy stoically then hunt the warbots for techs, but if you want a tech farmer char then choose the spy last.