Yes, no part of Soul Exchange stops you performing summons that turn.
You could activate Soul Exchange against one monster, then perform your normal summon for the turn, tributing that monster for a Lv5-6 one. Or you could do a regular normal summon and tribute that monster for something else. It's up to you.
No, you can't. Miracle Fertilizer says "You cannot Normal Summon or Set the turn you Special Summon a monster with this effect." That means if you've already normal summoned, it's impossible to fulfill that part of the card's effect. So you would not be allowed to activate it. This is similar to how you cannot have a battle phase and then activate Soul Exchange in main phase 2.
No, you do not 'tribute' the Synchro Material for a Synchro Summon. They are sent to the graveyard, not tributed. You can tribute an opponents synchro monster for "Assault Mode Activate!" to summon the assault mode monster from your deck.
Clearing up some possible confusion - Soul Exchange doesn't 'take' monsters, nor does it do anything to them on resolution, except for set up a condition that says you can tribute it as if it was one of your own. You tribute it therefore in exactly the same way as if it were on your side of the field. There is nothing stopping you tributing it, and a monster on your side of the field, to summon a Lv7 or higher monster. In fact if you used 2 Soul Exchanges, you could summon a Lv7+ monster with both of them.
Yes you can but you have to tribute one of your monsters, as well as the one of your opponent's monsters that you tributed using Soul Exchange.
Yes. Soul Exchange requires you to use it as a Tribute at the first opportunity.
Yes. You'd activate and resolve both Soul Exchanges individually. After that, the opponent now has two monsters you can tribute in place of your own. So these two can be tributed for the summon of a Lv7+ monster.
As per Soul Exchange's effect, one of the monsters for Amazoness Archer's cost can be one of the opponent's monsters.
Soul Exchange lists no such requirement. If you wanted to tribute summon, you don't need a monster on your side of the field for their monster to 'take the place of', you are simply using their monster to pay the tribute cost.
Yes you can, Soul Exchange simply offers a monster on your opponents side of the field as a tribute, as well as any others you may control.
Soul Exchange targets so you've already chosen which monster you'll be allowed to use, before you activate Psi-Impulse. You can't just decide to tribute a different one. Soul Exchange never forces you to actually use the monster, you're not obliged to use it at first opportunity. Even if you did target an opponent's Psychic monster for Soul Exchange, you are not forced to use it for Psi-Impulse if you'd rather use your own.
No. Soul Exchange's effect is to sacrifice one of your opponents monsters for a tribute summon. Blue-Eyes Shining Dragon can only be summoned by sacrificing a Blue-Eyes Ultimate Dragon, which can be summoned by fusing 3 Blue-Eyes White Dragons with Polymerization.
It would be for low levels- fire drake . Mid levels-summon me. high levels-summon pichu.