1. I am aware of history about term balts. If we don't name balts as balts and slavs as slavs, there might be completelly different picture - not this chauvinistical idea, that slavic evolved in empty place out of nowhere. People and history are connected and so are slavs. I feel we are having off-topic, because you wanted to distinguish baltic R1a from slavic, right? And let's leave out other haplogroups out of this. No Ia2 or other halpogroups, as R1a is already enough.
2. Morphology means little when different cultures collide. French morphology has nothing to do with german, even if french people were franks, who were germanic. What is the point of comparing morphology, if morphology is one of the weakest structural points of language - it is vocabulary that persist, even when the structure of original language dies out. Are you claiming that all slavic languages have the same morphological structure of language? Are you claiming that swedes uses articles for words, just like germans do? I have studied german, but hell no - no way german has the same morphology as english!!! Not to mention, that there are some distinct ways of pronounciation of sounds.
It is not like there are no excellent examples of how things happened to other people, like Twa pygmies in Kongo basin who uses bantu morphology, but they have distinct vocabulary for all things hunting and gathering related. That and bigger presence of B y-dna distinguishes them from bantu, even if they look alike now. Can we agree on this logic, that morphology of language matter less than vocabulary?
3. " In reallity, most linguists are agree..."
Science is not democracy that solves everything by voting - either someone is right and rest - are not. This is how science works.
What I have read is that there is actually wide variety of ideas and one of them is that prussian was dialectual continuity between slavic and eastern baltic. I do not want to touch this topic, as that requires further discussion what prussians had common with slavic from their early beginnings and what was later additions, but yes - prussians looks like documented link, that is most closest to slavic lingustics.
To be fair - there is no prussian language, but prussian languages. Only few of them had vocabulary written down. Actually, prussians were also very distinct culturally with distinct religious beliefs - they even practised urnfield culture, so it might be possible, that some groups assimilated into prussian. Assimilation works both ways.
I can only comment about living baltic languages and it is complicated already, as they became east baltic around 15th century, when so called non east baltic languages died out. Besides - naming someone east baltic, does not mean that there were no other dialects of baltic people to the east of them - we just do not know about them, as we have no language examples from pomeranian balts or other balts who are lost without name or mentions in history. The whole magic about baltic, is that it is not that much researched and I had a lot of reads from russian scientists in 90ties, that makes obsolete almost everything what is still published as norm and honestly - I am waiting when Putin will die(all for the love of read!) and russians will become normal people who will not be afraid to look at their history as it is. So should you.
4. Ok. Let's not touch languages, ethincities, if that is so confusing. To say what is accurate, we have to establish if so called baltic-slavic community(or whatever is meant by that) existed as long as baltic. I don't see YES to that question as answer. Because different cultures that are identifiable as baltic already existed and one of them later became proto slavic.
Let me also reply to Milan.M map Nr.2. His map at 300BC pictured proto-slavs around where was Milograd culture long after proto-balts went out and settled as different tribes. Actually it was not only dating that was wrong.
commons.wikimedia.org/wiki/File:Baltic_cultures_600-200_BC_SVG.svg
YES - they all are baltic.
5. Look, I see the confusion there already. We are actually talking about DIFFERENT THINGS. Can we for the sake of argument STAY AWAY from southern slavs? I do understand, that you are insterested in this topic, but 6th century AD was just start of slavic appearance in balkans and slavs had not yet assimilated Balkan people into their own, so they had no Ia2 or other haplogroups, that were strictly Balkan.
6. There are more influences of iranian languages(and by iranians I do mean - steppe nomads of iranian descent, not the ones, that dwelve in Persia) - don't let wiki page fool you, as it has mash of statements from various times. Iranian inluences on slavic has virtually not researched and you should look into future, that there will be new findings, because osetians(as last remnants of scythians) still exist and despite living among so many differently speaking people they still have many exciting similarities with slavic.
7. Zarubnitsy culture is waaaaay before linguistical proto-slavic - it would take them some centuries to even become proto-slavic.
If you are mentioning Veleti invasion - that's fine by me(although that might be a very large time offset, but whatever), that you agree that someone invaded baltic people who lived in proto-slavic area, as that solves question why you can't distinguish R1a of baltic and slavic.