no..

No, modern lithium ion batteries have no need for that and even if you do it, it will make no difference to the battery. In fact you can use it straight out of the box.

For LiIons, don't let it fall below 5%, best to start recharging at 15%

that not normal at all, by 4 hours sure finished download and charge
and phone just got slightly warm only since still charging
yes why not
no need like that 1
it got a cycle, just charge as you wish

In most cases, you should avoid full discharge cycles. Unlike NiCad batteries, lithium-ion batteries do not have a charge memory.

They have a limited number of charge cycles and letting it drop to 1% and then fully recharging would shave off one full cycle so if you purposely do it often, in the long run it could shorten the life a bit instead of just recharging it whenever the battery just kinda gets low in power.

i really hope this is software problem and not hardware problem..because on XDA sites also got few/many people got same problem..